Custom Truth subjects: use new Subject#check approach

Truth has evolved since we first started to write custom Truth subjects
and the recommended way to create chained subjects has changed.
According to [1], the recommended way is to use Subject#check as thus
the FailureStrategy is retained and (most importantly for us) a nice
failure message listing the complete chain of objects/methods is
generated.

Example for a reference in a failure message
before this change:
  path

with this change:
  robotCommentInfos.onlyElement().fixSuggestions().onlyElement()
    .replacements().onlyElement().path()

[1] https://google.github.io/truth/extension

Change-Id: I9a3b7a877af48a7e5f7d334cf210aa4a5867abb5

java/com/google/gerrit/common/data/testing/GroupReferenceSubject.java

@@ -20,14 +20,17 @@ import com.google.common.truth.ComparableSubject;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 
 public class GroupReferenceSubject extends Subject<GroupReferenceSubject, GroupReference> {
 
   public static GroupReferenceSubject assertThat(GroupReference group) {
-    return assertAbout(GroupReferenceSubject::new).that(group);
+    return assertAbout(groupReferences()).that(group);
+  }
+
+  public static Subject.Factory<GroupReferenceSubject, GroupReference> groupReferences() {
+    return GroupReferenceSubject::new;
   }
 
   private GroupReferenceSubject(FailureMetadata metadata, GroupReference group) {
@@ -37,12 +40,12 @@ public class GroupReferenceSubject extends Subject<GroupReferenceSubject, GroupR
   public ComparableSubject<?, AccountGroup.UUID> groupUuid() {
     isNotNull();
     GroupReference group = actual();
-    return Truth.assertThat(group.getUUID()).named("groupUuid");
+    return check("groupUuid()").that(group.getUUID());
   }
 
   public StringSubject name() {
     isNotNull();
     GroupReference group = actual();
-    return Truth.assertThat(group.getName()).named("name");
+    return check("name()").that(group.getName());
   }
 }

java/com/google/gerrit/extensions/common/testing/BUILD

@@ -6,6 +6,7 @@ java_library(
     deps = [
         "//java/com/google/gerrit/extensions:api",
         "//java/com/google/gerrit/truth",
+        "//lib:guava",
         "//lib/jgit/org.eclipse.jgit:jgit",
         "//lib/truth",
     ],

java/com/google/gerrit/extensions/common/testing/CommitInfoSubject.java

@@ -15,18 +15,23 @@
 package com.google.gerrit.extensions.common.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.extensions.common.testing.GitPersonSubject.gitPersons;
+import static com.google.gerrit.truth.ListSubject.elements;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.truth.ListSubject;
 
 public class CommitInfoSubject extends Subject<CommitInfoSubject, CommitInfo> {
 
   public static CommitInfoSubject assertThat(CommitInfo commitInfo) {
-    return assertAbout(CommitInfoSubject::new).that(commitInfo);
+    return assertAbout(commits()).that(commitInfo);
+  }
+
+  public static Subject.Factory<CommitInfoSubject, CommitInfo> commits() {
+    return CommitInfoSubject::new;
   }
 
   private CommitInfoSubject(FailureMetadata failureMetadata, CommitInfo commitInfo) {
@@ -36,31 +41,30 @@ public class CommitInfoSubject extends Subject<CommitInfoSubject, CommitInfo> {
   public StringSubject commit() {
     isNotNull();
     CommitInfo commitInfo = actual();
-    return Truth.assertThat(commitInfo.commit).named("commit");
+    return check("commit()").that(commitInfo.commit);
   }
 
   public ListSubject<CommitInfoSubject, CommitInfo> parents() {
     isNotNull();
     CommitInfo commitInfo = actual();
-    return ListSubject.assertThat(commitInfo.parents, CommitInfoSubject::assertThat)
+    return check("parents()").about(elements()).thatCustom(commitInfo.parents, commits());
-        .named("parents");
   }
 
   public GitPersonSubject committer() {
     isNotNull();
     CommitInfo commitInfo = actual();
-    return GitPersonSubject.assertThat(commitInfo.committer).named("committer");
+    return check("committer()").about(gitPersons()).that(commitInfo.committer);
   }
 
   public GitPersonSubject author() {
     isNotNull();
     CommitInfo commitInfo = actual();
-    return GitPersonSubject.assertThat(commitInfo.author).named("author");
+    return check("author()").about(gitPersons()).that(commitInfo.author);
   }
 
   public StringSubject message() {
     isNotNull();
     CommitInfo commitInfo = actual();
-    return Truth.assertThat(commitInfo.message).named("message");
+    return check("message").that(commitInfo.message);
   }
 }

java/com/google/gerrit/extensions/common/testing/ContentEntrySubject.java

@@ -14,21 +14,27 @@
 
 package com.google.gerrit.extensions.common.testing;
 
+import static com.google.common.truth.Fact.simpleFact;
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.truth.ListSubject.elements;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IntegerSubject;
 import com.google.common.truth.IterableSubject;
+import com.google.common.truth.StandardSubjectBuilder;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.DiffInfo.ContentEntry;
 import com.google.gerrit.truth.ListSubject;
 
 public class ContentEntrySubject extends Subject<ContentEntrySubject, ContentEntry> {
 
   public static ContentEntrySubject assertThat(ContentEntry contentEntry) {
-    return assertAbout(ContentEntrySubject::new).that(contentEntry);
+    return assertAbout(contentEntries()).that(contentEntry);
+  }
+
+  public static Subject.Factory<ContentEntrySubject, ContentEntry> contentEntries() {
+    return ContentEntrySubject::new;
   }
 
   private ContentEntrySubject(FailureMetadata failureMetadata, ContentEntry contentEntry) {
@@ -38,54 +44,54 @@ public class ContentEntrySubject extends Subject<ContentEntrySubject, ContentEnt
   public void isDueToRebase() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    Truth.assertWithMessage("Entry should be marked 'dueToRebase'")
+    if (contentEntry.dueToRebase == null || !contentEntry.dueToRebase) {
-        .that(contentEntry.dueToRebase)
+      failWithActual(simpleFact("expected entry to be marked 'dueToRebase'"));
-        .named("dueToRebase")
+    }
-        .isTrue();
   }
 
   public void isNotDueToRebase() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    Truth.assertWithMessage("Entry should not be marked 'dueToRebase'")
+    if (contentEntry.dueToRebase != null && contentEntry.dueToRebase) {
-        .that(contentEntry.dueToRebase)
+      failWithActual(simpleFact("expected entry not to be marked 'dueToRebase'"));
-        .named("dueToRebase")
+    }
-        .isNull();
   }
 
   public ListSubject<StringSubject, String> commonLines() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    return ListSubject.assertThat(contentEntry.ab, Truth::assertThat).named("common lines");
+    return check("commonLines()")
+        .about(elements())
+        .that(contentEntry.ab, StandardSubjectBuilder::that);
   }
 
   public ListSubject<StringSubject, String> linesOfA() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    return ListSubject.assertThat(contentEntry.a, Truth::assertThat).named("lines of 'a'");
+    return check("linesOfA()").about(elements()).that(contentEntry.a, StandardSubjectBuilder::that);
   }
 
   public ListSubject<StringSubject, String> linesOfB() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    return ListSubject.assertThat(contentEntry.b, Truth::assertThat).named("lines of 'b'");
+    return check("linesOfB()").about(elements()).that(contentEntry.b, StandardSubjectBuilder::that);
   }
 
   public IterableSubject intralineEditsOfA() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    return Truth.assertThat(contentEntry.editA).named("intraline edits of 'a'");
+    return check("intralineEditsOfA()").that(contentEntry.editA);
   }
 
   public IterableSubject intralineEditsOfB() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    return Truth.assertThat(contentEntry.editB).named("intraline edits of 'b'");
+    return check("intralineEditsOfB()").that(contentEntry.editB);
   }
 
   public IntegerSubject numberOfSkippedLines() {
     isNotNull();
     ContentEntry contentEntry = actual();
-    return Truth.assertThat(contentEntry.skip).named("number of skipped lines");
+    return check("numberOfSkippedLines()").that(contentEntry.skip);
   }
 }

java/com/google/gerrit/extensions/common/testing/DiffInfoSubject.java

@@ -15,11 +15,12 @@
 package com.google.gerrit.extensions.common.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.extensions.common.testing.FileMetaSubject.fileMetas;
+import static com.google.gerrit.truth.ListSubject.elements;
 
 import com.google.common.truth.ComparableSubject;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.ChangeType;
 import com.google.gerrit.extensions.common.DiffInfo;
 import com.google.gerrit.extensions.common.DiffInfo.ContentEntry;
@@ -38,25 +39,26 @@ public class DiffInfoSubject extends Subject<DiffInfoSubject, DiffInfo> {
   public ListSubject<ContentEntrySubject, ContentEntry> content() {
     isNotNull();
     DiffInfo diffInfo = actual();
-    return ListSubject.assertThat(diffInfo.content, ContentEntrySubject::assertThat)
+    return check("content()")
-        .named("content");
+        .about(elements())
+        .thatCustom(diffInfo.content, ContentEntrySubject.contentEntries());
   }
 
   public ComparableSubject<?, ChangeType> changeType() {
     isNotNull();
     DiffInfo diffInfo = actual();
-    return Truth.assertThat(diffInfo.changeType).named("changeType");
+    return check("changeType()").that(diffInfo.changeType);
   }
 
   public FileMetaSubject metaA() {
     isNotNull();
     DiffInfo diffInfo = actual();
-    return FileMetaSubject.assertThat(diffInfo.metaA).named("metaA");
+    return check("metaA()").about(fileMetas()).that(diffInfo.metaA);
   }
 
   public FileMetaSubject metaB() {
     isNotNull();
     DiffInfo diffInfo = actual();
-    return FileMetaSubject.assertThat(diffInfo.metaB).named("metaB");
+    return check("metaB()").about(fileMetas()).that(diffInfo.metaB);
   }
 }

java/com/google/gerrit/extensions/common/testing/EditInfoSubject.java

@@ -15,11 +15,11 @@
 package com.google.gerrit.extensions.common.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.extensions.common.testing.CommitInfoSubject.commits;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.truth.OptionalSubject;
 import java.util.Optional;
@@ -27,12 +27,16 @@ import java.util.Optional;
 public class EditInfoSubject extends Subject<EditInfoSubject, EditInfo> {
 
   public static EditInfoSubject assertThat(EditInfo editInfo) {
-    return assertAbout(EditInfoSubject::new).that(editInfo);
+    return assertAbout(edits()).that(editInfo);
+  }
+
+  private static Subject.Factory<EditInfoSubject, EditInfo> edits() {
+    return EditInfoSubject::new;
   }
 
   public static OptionalSubject<EditInfoSubject, EditInfo> assertThat(
       Optional<EditInfo> editInfoOptional) {
-    return OptionalSubject.assertThat(editInfoOptional, EditInfoSubject::assertThat);
+    return OptionalSubject.assertThat(editInfoOptional, edits());
   }
 
   private EditInfoSubject(FailureMetadata failureMetadata, EditInfo editInfo) {
@@ -42,12 +46,12 @@ public class EditInfoSubject extends Subject<EditInfoSubject, EditInfo> {
   public CommitInfoSubject commit() {
     isNotNull();
     EditInfo editInfo = actual();
-    return CommitInfoSubject.assertThat(editInfo.commit).named("commit");
+    return check("commit()").about(commits()).that(editInfo.commit);
   }
 
   public StringSubject baseRevision() {
     isNotNull();
     EditInfo editInfo = actual();
-    return Truth.assertThat(editInfo.baseRevision).named("baseRevision");
+    return check("baseRevision()").that(editInfo.baseRevision);
   }
 }

java/com/google/gerrit/extensions/common/testing/FileInfoSubject.java

@@ -20,7 +20,6 @@ import com.google.common.truth.ComparableSubject;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IntegerSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.FileInfo;
 
 public class FileInfoSubject extends Subject<FileInfoSubject, FileInfo> {
@@ -36,18 +35,18 @@ public class FileInfoSubject extends Subject<FileInfoSubject, FileInfo> {
   public IntegerSubject linesInserted() {
     isNotNull();
     FileInfo fileInfo = actual();
-    return Truth.assertThat(fileInfo.linesInserted).named("linesInserted");
+    return check("linesInserted()").that(fileInfo.linesInserted);
   }
 
   public IntegerSubject linesDeleted() {
     isNotNull();
     FileInfo fileInfo = actual();
-    return Truth.assertThat(fileInfo.linesDeleted).named("linesDeleted");
+    return check("linesDeleted()").that(fileInfo.linesDeleted);
   }
 
   public ComparableSubject<?, Character> status() {
     isNotNull();
     FileInfo fileInfo = actual();
-    return Truth.assertThat(fileInfo.status).named("status");
+    return check("status()").that(fileInfo.status);
   }
 }

java/com/google/gerrit/extensions/common/testing/FileMetaSubject.java

@@ -19,13 +19,16 @@ import static com.google.common.truth.Truth.assertAbout;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IntegerSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.DiffInfo.FileMeta;
 
 public class FileMetaSubject extends Subject<FileMetaSubject, FileMeta> {
 
   public static FileMetaSubject assertThat(FileMeta fileMeta) {
-    return assertAbout(FileMetaSubject::new).that(fileMeta);
+    return assertAbout(fileMetas()).that(fileMeta);
+  }
+
+  public static Subject.Factory<FileMetaSubject, FileMeta> fileMetas() {
+    return FileMetaSubject::new;
   }
 
   private FileMetaSubject(FailureMetadata failureMetadata, FileMeta fileMeta) {
@@ -35,6 +38,6 @@ public class FileMetaSubject extends Subject<FileMetaSubject, FileMeta> {
   public IntegerSubject totalLineCount() {
     isNotNull();
     FileMeta fileMeta = actual();
-    return Truth.assertThat(fileMeta.lines).named("total line count");
+    return check("totalLineCount()").that(fileMeta.lines);
   }
 }

java/com/google/gerrit/extensions/common/testing/FixReplacementInfoSubject.java

@@ -15,18 +15,22 @@
 package com.google.gerrit.extensions.common.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.extensions.common.testing.RangeSubject.ranges;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.FixReplacementInfo;
 
 public class FixReplacementInfoSubject
     extends Subject<FixReplacementInfoSubject, FixReplacementInfo> {
 
   public static FixReplacementInfoSubject assertThat(FixReplacementInfo fixReplacementInfo) {
-    return assertAbout(FixReplacementInfoSubject::new).that(fixReplacementInfo);
+    return assertAbout(fixReplacements()).that(fixReplacementInfo);
+  }
+
+  public static Subject.Factory<FixReplacementInfoSubject, FixReplacementInfo> fixReplacements() {
+    return FixReplacementInfoSubject::new;
   }
 
   private FixReplacementInfoSubject(
@@ -35,14 +39,17 @@ public class FixReplacementInfoSubject
   }
 
   public StringSubject path() {
-    return Truth.assertThat(actual().path).named("path");
+    isNotNull();
+    return check("path()").that(actual().path);
   }
 
   public RangeSubject range() {
-    return RangeSubject.assertThat(actual().range).named("range");
+    isNotNull();
+    return check("range()").about(ranges()).that(actual().range);
   }
 
   public StringSubject replacement() {
-    return Truth.assertThat(actual().replacement).named("replacement");
+    isNotNull();
+    return check("replacement()").that(actual().replacement);
   }
 }

java/com/google/gerrit/extensions/common/testing/FixSuggestionInfoSubject.java

@@ -15,6 +15,8 @@
 package com.google.gerrit.extensions.common.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.extensions.common.testing.FixReplacementInfoSubject.fixReplacements;
+import static com.google.gerrit.truth.ListSubject.elements;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StringSubject;
@@ -27,7 +29,11 @@ import com.google.gerrit.truth.ListSubject;
 public class FixSuggestionInfoSubject extends Subject<FixSuggestionInfoSubject, FixSuggestionInfo> {
 
   public static FixSuggestionInfoSubject assertThat(FixSuggestionInfo fixSuggestionInfo) {
-    return assertAbout(FixSuggestionInfoSubject::new).that(fixSuggestionInfo);
+    return assertAbout(fixSuggestions()).that(fixSuggestionInfo);
+  }
+
+  public static Subject.Factory<FixSuggestionInfoSubject, FixSuggestionInfo> fixSuggestions() {
+    return FixSuggestionInfoSubject::new;
   }
 
   private FixSuggestionInfoSubject(
@@ -40,8 +46,10 @@ public class FixSuggestionInfoSubject extends Subject<FixSuggestionInfoSubject,
   }
 
   public ListSubject<FixReplacementInfoSubject, FixReplacementInfo> replacements() {
-    return ListSubject.assertThat(actual().replacements, FixReplacementInfoSubject::assertThat)
+    isNotNull();
-        .named("replacements");
+    return check("replacements()")
+        .about(elements())
+        .thatCustom(actual().replacements, fixReplacements());
   }
 
   public FixReplacementInfoSubject onlyReplacement() {
@@ -49,6 +57,7 @@ public class FixSuggestionInfoSubject extends Subject<FixSuggestionInfoSubject,
   }
 
   public StringSubject description() {
-    return Truth.assertThat(actual().description).named("description");
+    isNotNull();
+    return check("description()").that(actual().description);
   }
 }

java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.extensions.common.testing;
 
+import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.truth.ComparableSubject;
@@ -21,7 +22,6 @@ import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IntegerSubject;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.common.GitPerson;
 import java.sql.Timestamp;
 import java.util.Date;
@@ -30,7 +30,11 @@ import org.eclipse.jgit.lib.PersonIdent;
 public class GitPersonSubject extends Subject<GitPersonSubject, GitPerson> {
 
   public static GitPersonSubject assertThat(GitPerson gitPerson) {
-    return assertAbout(GitPersonSubject::new).that(gitPerson);
+    return assertAbout(gitPersons()).that(gitPerson);
+  }
+
+  public static Factory<GitPersonSubject, GitPerson> gitPersons() {
+    return GitPersonSubject::new;
   }
 
   private GitPersonSubject(FailureMetadata failureMetadata, GitPerson gitPerson) {
@@ -40,30 +44,30 @@ public class GitPersonSubject extends Subject<GitPersonSubject, GitPerson> {
   public StringSubject name() {
     isNotNull();
     GitPerson gitPerson = actual();
-    return Truth.assertThat(gitPerson.name).named("name");
+    return check("name()").that(gitPerson.name);
   }
 
   public StringSubject email() {
     isNotNull();
     GitPerson gitPerson = actual();
-    return Truth.assertThat(gitPerson.email).named("email");
+    return check("email()").that(gitPerson.email);
   }
 
   public ComparableSubject<?, Timestamp> date() {
     isNotNull();
     GitPerson gitPerson = actual();
-    return Truth.assertThat(gitPerson.date).named("date");
+    return check("date()").that(gitPerson.date);
   }
 
   public IntegerSubject tz() {
     isNotNull();
     GitPerson gitPerson = actual();
-    return Truth.assertThat(gitPerson.tz).named("tz");
+    return check("tz()").that(gitPerson.tz);
   }
 
   public void hasSameDateAs(GitPerson other) {
+    checkNotNull(other, "'other' GitPerson must not be null");
     isNotNull();
-    assertThat(other).named("other").isNotNull();
     date().isEqualTo(other.date);
     tz().isEqualTo(other.tz);
   }
@@ -72,9 +76,7 @@ public class GitPersonSubject extends Subject<GitPersonSubject, GitPerson> {
     isNotNull();
     name().isEqualTo(ident.getName());
     email().isEqualTo(ident.getEmailAddress());
-    Truth.assertThat(new Date(actual().date.getTime()))
+    check("roundedDate()").that(new Date(actual().date.getTime())).isEqualTo(ident.getWhen());
-        .named("rounded date")
-        .isEqualTo(ident.getWhen());
     tz().isEqualTo(ident.getTimeZoneOffset());
   }
 }

java/com/google/gerrit/extensions/common/testing/RangeSubject.java

@@ -14,19 +14,22 @@
 
 package com.google.gerrit.extensions.common.testing;
 
-import static com.google.common.truth.Fact.fact;
+import static com.google.common.truth.Fact.simpleFact;
 import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IntegerSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.client.Comment;
 
 public class RangeSubject extends Subject<RangeSubject, Comment.Range> {
 
   public static RangeSubject assertThat(Comment.Range range) {
-    return assertAbout(RangeSubject::new).that(range);
+    return assertAbout(ranges()).that(range);
+  }
+
+  public static Subject.Factory<RangeSubject, Comment.Range> ranges() {
+    return RangeSubject::new;
   }
 
   private RangeSubject(FailureMetadata failureMetadata, Comment.Range range) {
@@ -34,32 +37,32 @@ public class RangeSubject extends Subject<RangeSubject, Comment.Range> {
   }
 
   public IntegerSubject startLine() {
-    return Truth.assertThat(actual().startLine).named("startLine");
+    return check("startLine()").that(actual().startLine);
   }
 
   public IntegerSubject startCharacter() {
-    return Truth.assertThat(actual().startCharacter).named("startCharacter");
+    return check("startCharacter()").that(actual().startCharacter);
   }
 
   public IntegerSubject endLine() {
-    return Truth.assertThat(actual().endLine).named("endLine");
+    return check("endLine()").that(actual().endLine);
   }
 
   public IntegerSubject endCharacter() {
-    return Truth.assertThat(actual().endCharacter).named("endCharacter");
+    return check("endCharacter()").that(actual().endCharacter);
   }
 
   public void isValid() {
     isNotNull();
     if (!actual().isValid()) {
-      failWithoutActual(fact("expected", "valid"));
+      failWithActual(simpleFact("expected to be valid"));
     }
   }
 
   public void isInvalid() {
     isNotNull();
     if (actual().isValid()) {
-      failWithoutActual(fact("expected", "not valid"));
+      failWithActual(simpleFact("expected to be invalid"));
     }
   }
 }

java/com/google/gerrit/extensions/common/testing/RobotCommentInfoSubject.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.extensions.common.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static com.google.gerrit.truth.ListSubject.elements;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
@@ -27,12 +28,15 @@ public class RobotCommentInfoSubject extends Subject<RobotCommentInfoSubject, Ro
 
   public static ListSubject<RobotCommentInfoSubject, RobotCommentInfo> assertThatList(
       List<RobotCommentInfo> robotCommentInfos) {
-    return ListSubject.assertThat(robotCommentInfos, RobotCommentInfoSubject::assertThat)
+    return ListSubject.assertThat(robotCommentInfos, robotComments()).named("robotCommentInfos");
-        .named("robotCommentInfos");
   }
 
   public static RobotCommentInfoSubject assertThat(RobotCommentInfo robotCommentInfo) {
-    return assertAbout(RobotCommentInfoSubject::new).that(robotCommentInfo);
+    return assertAbout(robotComments()).that(robotCommentInfo);
+  }
+
+  private static Factory<RobotCommentInfoSubject, RobotCommentInfo> robotComments() {
+    return RobotCommentInfoSubject::new;
   }
 
   private RobotCommentInfoSubject(
@@ -41,8 +45,9 @@ public class RobotCommentInfoSubject extends Subject<RobotCommentInfoSubject, Ro
   }
 
   public ListSubject<FixSuggestionInfoSubject, FixSuggestionInfo> fixSuggestions() {
-    return ListSubject.assertThat(actual().fixSuggestions, FixSuggestionInfoSubject::assertThat)
+    return check("fixSuggestions()")
-        .named("fixSuggestions");
+        .about(elements())
+        .thatCustom(actual().fixSuggestions, FixSuggestionInfoSubject.fixSuggestions());
   }
 
   public FixSuggestionInfoSubject onlyFixSuggestion() {

java/com/google/gerrit/extensions/restapi/testing/BinaryResultSubject.java

@@ -20,7 +20,6 @@ import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.PrimitiveByteArraySubject;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.truth.OptionalSubject;
 import java.io.ByteArrayOutputStream;
@@ -30,12 +29,16 @@ import java.util.Optional;
 public class BinaryResultSubject extends Subject<BinaryResultSubject, BinaryResult> {
 
   public static BinaryResultSubject assertThat(BinaryResult binaryResult) {
-    return assertAbout(BinaryResultSubject::new).that(binaryResult);
+    return assertAbout(binaryResults()).that(binaryResult);
+  }
+
+  private static Subject.Factory<BinaryResultSubject, BinaryResult> binaryResults() {
+    return BinaryResultSubject::new;
   }
 
   public static OptionalSubject<BinaryResultSubject, BinaryResult> assertThat(
       Optional<BinaryResult> binaryResultOptional) {
-    return OptionalSubject.assertThat(binaryResultOptional, BinaryResultSubject::assertThat);
+    return OptionalSubject.assertThat(binaryResultOptional, binaryResults());
   }
 
   private BinaryResultSubject(FailureMetadata failureMetadata, BinaryResult binaryResult) {
@@ -48,7 +51,7 @@ public class BinaryResultSubject extends Subject<BinaryResultSubject, BinaryResu
     // be used afterwards. Besides, closing it doesn't have an effect for most
     // implementations of a BinaryResult.
     BinaryResult binaryResult = actual();
-    return Truth.assertThat(binaryResult.asString());
+    return check("asString()").that(binaryResult.asString());
   }
 
   public PrimitiveByteArraySubject bytes() throws IOException {
@@ -60,6 +63,6 @@ public class BinaryResultSubject extends Subject<BinaryResultSubject, BinaryResu
     ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
     binaryResult.writeTo(byteArrayOutputStream);
     byte[] bytes = byteArrayOutputStream.toByteArray();
-    return Truth.assertThat(bytes);
+    return check("bytes()").that(bytes);
   }
 }

java/com/google/gerrit/git/testing/CommitSubject.java

@@ -19,7 +19,6 @@ import static java.util.concurrent.TimeUnit.SECONDS;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import java.sql.Timestamp;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.revwalk.RevCommit;
@@ -69,9 +68,7 @@ public class CommitSubject extends Subject<CommitSubject, RevCommit> {
   public void hasCommitMessage(String expectedCommitMessage) {
     isNotNull();
     RevCommit commit = actual();
-    Truth.assertThat(commit.getFullMessage())
+    check("commitMessage()").that(commit.getFullMessage()).isEqualTo(expectedCommitMessage);
-        .named("commit message")
-        .isEqualTo(expectedCommitMessage);
   }
 
   /**
@@ -84,7 +81,7 @@ public class CommitSubject extends Subject<CommitSubject, RevCommit> {
     RevCommit commit = actual();
     long timestampDiffMs =
         Math.abs(commit.getCommitTime() * 1000L - expectedCommitTimestamp.getTime());
-    Truth.assertThat(timestampDiffMs).named("commit timestamp diff").isAtMost(SECONDS.toMillis(1));
+    check("commitTimestampDiff()").that(timestampDiffMs).isAtMost(SECONDS.toMillis(1));
   }
 
   /**
@@ -95,6 +92,6 @@ public class CommitSubject extends Subject<CommitSubject, RevCommit> {
   public void hasSha1(ObjectId expectedSha1) {
     isNotNull();
     RevCommit commit = actual();
-    Truth.assertThat(commit).named("SHA1").isEqualTo(expectedSha1);
+    check("sha1()").that(commit).isEqualTo(expectedSha1);
   }
 }

java/com/google/gerrit/git/testing/ObjectIdSubject.java

@@ -18,12 +18,15 @@ import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import org.eclipse.jgit.lib.ObjectId;
 
 public class ObjectIdSubject extends Subject<ObjectIdSubject, ObjectId> {
   public static ObjectIdSubject assertThat(ObjectId objectId) {
-    return assertAbout(ObjectIdSubject::new).that(objectId);
+    return assertAbout(objectIds()).that(objectId);
+  }
+
+  public static Factory<ObjectIdSubject, ObjectId> objectIds() {
+    return ObjectIdSubject::new;
   }
 
   private ObjectIdSubject(FailureMetadata metadata, ObjectId actual) {
@@ -33,6 +36,6 @@ public class ObjectIdSubject extends Subject<ObjectIdSubject, ObjectId> {
   public void hasName(String expectedName) {
     isNotNull();
     ObjectId objectId = actual();
-    Truth.assertThat(objectId.getName()).named("name").isEqualTo(expectedName);
+    check("name()").that(objectId.getName()).isEqualTo(expectedName);
   }
 }

java/com/google/gerrit/git/testing/PushResultSubject.java

@@ -16,7 +16,6 @@ package com.google.gerrit.git.testing;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.truth.Truth.assertAbout;
-import static java.util.stream.Collectors.joining;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Splitter;
@@ -25,11 +24,10 @@ import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Maps;
 import com.google.common.truth.FailureMetadata;
+import com.google.common.truth.StreamSubject;
 import com.google.common.truth.Subject;
 import com.google.common.truth.Truth;
-import com.google.common.truth.Truth8;
 import com.google.gerrit.common.Nullable;
-import java.util.Arrays;
 import org.eclipse.jgit.transport.PushResult;
 import org.eclipse.jgit.transport.RemoteRefUpdate;
 
@@ -43,7 +41,8 @@ public class PushResultSubject extends Subject<PushResultSubject, PushResult> {
   }
 
   public void hasNoMessages() {
-    Truth.assertWithMessage("expected no messages")
+    check()
+        .withMessage("expected no messages")
         .that(Strings.nullToEmpty(trimMessages()))
         .isEqualTo("");
   }
@@ -51,14 +50,14 @@ public class PushResultSubject extends Subject<PushResultSubject, PushResult> {
   public void hasMessages(String... expectedLines) {
     checkArgument(expectedLines.length > 0, "use hasNoMessages()");
     isNotNull();
-    Truth.assertThat(trimMessages()).isEqualTo(Arrays.stream(expectedLines).collect(joining("\n")));
+    check("messages()").that(trimMessages()).isEqualTo(String.join("\n", expectedLines));
   }
 
   public void containsMessages(String... expectedLines) {
     checkArgument(expectedLines.length > 0, "use hasNoMessages()");
     isNotNull();
     Iterable<String> got = Splitter.on("\n").split(trimMessages());
-    Truth.assertThat(got).containsAllIn(expectedLines).inOrder();
+    check("messages()").that(got).containsAllIn(expectedLines).inOrder();
   }
 
   private String trimMessages() {
@@ -90,10 +89,7 @@ public class PushResultSubject extends Subject<PushResultSubject, PushResult> {
               messages, Throwables.getStackTraceAsString(e));
       return;
     }
-    Truth.assertThat(actual)
+    check("processedCommands()").that(actual).containsExactlyEntriesIn(expected).inOrder();
-        .named("processed commands")
-        .containsExactlyEntriesIn(expected)
-        .inOrder();
   }
 
   @VisibleForTesting
@@ -129,7 +125,9 @@ public class PushResultSubject extends Subject<PushResultSubject, PushResult> {
   }
 
   public RemoteRefUpdateSubject onlyRef(String refName) {
-    Truth8.assertThat(actual().getRemoteUpdates().stream().map(RemoteRefUpdate::getRemoteName))
+    check("setOfRefs()")
+        .about(StreamSubject.streams())
+        .that(actual().getRemoteUpdates().stream().map(RemoteRefUpdate::getRemoteName))
         .named("set of refs")
         .containsExactly(refName);
     return ref(refName);

java/com/google/gerrit/proto/testing/SerializedClassSubject.java

@@ -15,9 +15,8 @@
 package com.google.gerrit.proto.testing;
 
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
+import static com.google.common.truth.Fact.simpleFact;
 import static com.google.common.truth.Truth.assertAbout;
-import static com.google.common.truth.Truth.assertThat;
-import static com.google.common.truth.Truth.assertWithMessage;
 
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
@@ -67,21 +66,22 @@ public class SerializedClassSubject extends Subject<SerializedClassSubject, Clas
 
   public void isAbstract() {
     isNotNull();
-    assertWithMessage("expected class %s to be abstract", actual().getName())
+    if (!Modifier.isAbstract(actual().getModifiers())) {
-        .that(Modifier.isAbstract(actual().getModifiers()))
+      failWithActual(simpleFact("expected class to be abstract"));
-        .isTrue();
+    }
   }
 
   public void isConcrete() {
     isNotNull();
-    assertWithMessage("expected class %s to be concrete", actual().getName())
+    if (Modifier.isAbstract(actual().getModifiers())) {
-        .that(!Modifier.isAbstract(actual().getModifiers()))
+      failWithActual(simpleFact("expected class to be concrete"));
-        .isTrue();
+    }
   }
 
   public void hasFields(Map<String, Type> expectedFields) {
     isConcrete();
-    assertThat(
+    check("fields()")
+        .that(
             FieldUtils.getAllFieldsList(actual()).stream()
                 .filter(f -> !Modifier.isStatic(f.getModifiers()))
                 .collect(toImmutableMap(Field::getName, Field::getGenericType)))
@@ -91,20 +91,20 @@ public class SerializedClassSubject extends Subject<SerializedClassSubject, Clas
   public void hasAutoValueMethods(Map<String, Type> expectedMethods) {
     // Would be nice if we could check clazz is an @AutoValue, but the retention is not RUNTIME.
     isAbstract();
-    assertThat(
+    check("noArgumentAbstractMethodsOn(%s)", actual().getName())
+        .that(
             Arrays.stream(actual().getDeclaredMethods())
                 .filter(m -> !Modifier.isStatic(m.getModifiers()))
                 .filter(m -> Modifier.isAbstract(m.getModifiers()))
                 .filter(m -> m.getParameters().length == 0)
                 .collect(toImmutableMap(Method::getName, Method::getGenericReturnType)))
-        .named("no-argument abstract methods on %s", actual().getName())
         .isEqualTo(expectedMethods);
   }
 
   public void extendsClass(Type superclassType) {
     isNotNull();
-    assertThat(actual().getGenericSuperclass())
+    check("superclass(%s)", actual().getName())
-        .named("superclass of %s", actual().getName())
+        .that(actual().getGenericSuperclass())
         .isEqualTo(superclassType);
   }
 }

java/com/google/gerrit/server/group/testing/InternalGroupSubject.java

@@ -23,7 +23,6 @@ import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IterableSubject;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.server.group.InternalGroup;
 import java.sql.Timestamp;
@@ -32,7 +31,11 @@ import org.eclipse.jgit.lib.ObjectId;
 public class InternalGroupSubject extends Subject<InternalGroupSubject, InternalGroup> {
 
   public static InternalGroupSubject assertThat(InternalGroup group) {
-    return assertAbout(InternalGroupSubject::new).that(group);
+    return assertAbout(internalGroups()).that(group);
+  }
+
+  public static Subject.Factory<InternalGroupSubject, InternalGroup> internalGroups() {
+    return InternalGroupSubject::new;
   }
 
   private InternalGroupSubject(FailureMetadata metadata, InternalGroup actual) {
@@ -42,66 +45,66 @@ public class InternalGroupSubject extends Subject<InternalGroupSubject, Internal
   public ComparableSubject<?, AccountGroup.UUID> groupUuid() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getGroupUUID()).named("groupUuid");
+    return check("groupUuid()").that(group.getGroupUUID());
   }
 
   public ComparableSubject<?, AccountGroup.NameKey> nameKey() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getNameKey()).named("nameKey");
+    return check("nameKey()").that(group.getNameKey());
   }
 
   public StringSubject name() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getName()).named("name");
+    return check("name()").that(group.getName());
   }
 
-  public DefaultSubject id() {
+  public Subject<DefaultSubject, Object> id() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getId()).named("id");
+    return check("id()").that(group.getId());
   }
 
   public StringSubject description() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getDescription()).named("description");
+    return check("description()").that(group.getDescription());
   }
 
   public ComparableSubject<?, AccountGroup.UUID> ownerGroupUuid() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getOwnerGroupUUID()).named("ownerGroupUuid");
+    return check("ownerGroupUuid()").that(group.getOwnerGroupUUID());
   }
 
   public BooleanSubject visibleToAll() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.isVisibleToAll()).named("visibleToAll");
+    return check("visibleToAll()").that(group.isVisibleToAll());
   }
 
   public ComparableSubject<?, Timestamp> createdOn() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getCreatedOn()).named("createdOn");
+    return check("createdOn()").that(group.getCreatedOn());
   }
 
   public IterableSubject members() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getMembers()).named("members");
+    return check("members()").that(group.getMembers());
   }
 
   public IterableSubject subgroups() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getSubgroups()).named("subgroups");
+    return check("subgroups()").that(group.getSubgroups());
   }
 
   public ComparableSubject<?, ObjectId> refState() {
     isNotNull();
     InternalGroup group = actual();
-    return Truth.assertThat(group.getRefState()).named("refState");
+    return check("refState()").that(group.getRefState());
   }
 }

java/com/google/gerrit/truth/ListSubject.java

@@ -18,28 +18,34 @@ import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.truth.Fact.fact;
 import static com.google.common.truth.Truth.assertAbout;
 
+import com.google.common.collect.Iterables;
+import com.google.common.truth.CustomSubjectBuilder;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IterableSubject;
+import com.google.common.truth.StandardSubjectBuilder;
 import com.google.common.truth.Subject;
 import java.util.List;
-import java.util.function.Function;
+import java.util.function.BiFunction;
 
 public class ListSubject<S extends Subject<S, E>, E> extends IterableSubject {
 
-  private final Function<E, S> elementAssertThatFunction;
+  private final BiFunction<StandardSubjectBuilder, E, S> elementSubjectCreator;
 
-  @SuppressWarnings("unchecked")
   public static <S extends Subject<S, E>, E> ListSubject<S, E> assertThat(
-      List<E> list, Function<E, S> elementAssertThatFunction) {
+      List<E> list, Subject.Factory<S, E> subjectFactory) {
-    // The ListSubjectFactory always returns ListSubjects. -> Casting is appropriate.
+    return assertAbout(elements()).thatCustom(list, subjectFactory);
-    return (ListSubject<S, E>)
+  }
-        assertAbout(new ListSubjectFactory<>(elementAssertThatFunction)).that(list);
+
+  public static CustomSubjectBuilder.Factory<ListSubjectBuilder> elements() {
+    return ListSubjectBuilder::new;
   }
 
   private ListSubject(
-      FailureMetadata failureMetadata, List<E> list, Function<E, S> elementAssertThatFunction) {
+      FailureMetadata failureMetadata,
+      List<E> list,
+      BiFunction<StandardSubjectBuilder, E, S> elementSubjectCreator) {
     super(failureMetadata, list);
-    this.elementAssertThatFunction = elementAssertThatFunction;
+    this.elementSubjectCreator = elementSubjectCreator;
   }
 
   public S element(int index) {
@@ -49,20 +55,21 @@ public class ListSubject<S extends Subject<S, E>, E> extends IterableSubject {
     if (index >= list.size()) {
       failWithoutActual(fact("expected to have element at index", index));
     }
-    return elementAssertThatFunction.apply(list.get(index));
+    return elementSubjectCreator.apply(check("element(%s)", index), list.get(index));
   }
 
   public S onlyElement() {
     isNotNull();
     hasSize(1);
-    return element(0);
+    List<E> list = getActualList();
+    return elementSubjectCreator.apply(check("onlyElement()"), Iterables.getOnlyElement(list));
   }
 
   public S lastElement() {
     isNotNull();
     isNotEmpty();
     List<E> list = getActualList();
-    return element(list.size() - 1);
+    return elementSubjectCreator.apply(check("lastElement()"), Iterables.getLast(list));
   }
 
   @SuppressWarnings("unchecked")
@@ -78,20 +85,20 @@ public class ListSubject<S extends Subject<S, E>, E> extends IterableSubject {
     return (ListSubject<S, E>) super.named(s, objects);
   }
 
-  private static class ListSubjectFactory<S extends Subject<S, T>, T>
+  public static class ListSubjectBuilder extends CustomSubjectBuilder {
-      implements Subject.Factory<IterableSubject, Iterable<?>> {
 
-    private Function<T, S> elementAssertThatFunction;
+    ListSubjectBuilder(FailureMetadata failureMetadata) {
-
+      super(failureMetadata);
-    ListSubjectFactory(Function<T, S> elementAssertThatFunction) {
-      this.elementAssertThatFunction = elementAssertThatFunction;
     }
 
-    @SuppressWarnings("unchecked")
+    public <S extends Subject<S, E>, E> ListSubject<S, E> thatCustom(
-    @Override
+        List<E> list, Subject.Factory<S, E> subjectFactory) {
-    public ListSubject<S, T> createSubject(FailureMetadata failureMetadata, Iterable<?> objects) {
+      return that(list, (builder, element) -> builder.about(subjectFactory).that(element));
-      // The constructor of ListSubject only accepts lists. -> Casting is appropriate.
+    }
-      return new ListSubject<>(failureMetadata, (List<T>) objects, elementAssertThatFunction);
+
+    public <S extends Subject<S, E>, E> ListSubject<S, E> that(
+        List<E> list, BiFunction<StandardSubjectBuilder, E, S> elementSubjectCreator) {
+      return new ListSubject<>(metadata(), list, elementSubjectCreator);
     }
   }
 }

java/com/google/gerrit/truth/OptionalSubject.java

@@ -17,41 +17,52 @@ package com.google.gerrit.truth;
 import static com.google.common.truth.Fact.fact;
 import static com.google.common.truth.Truth.assertAbout;
 
+import com.google.common.truth.CustomSubjectBuilder;
 import com.google.common.truth.DefaultSubject;
 import com.google.common.truth.FailureMetadata;
+import com.google.common.truth.StandardSubjectBuilder;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import java.util.Optional;
+import java.util.function.BiFunction;
 import java.util.function.Function;
 
 public class OptionalSubject<S extends Subject<S, ? super T>, T>
     extends Subject<OptionalSubject<S, T>, Optional<T>> {
 
-  private final Function<? super T, ? extends S> valueAssertThatFunction;
+  private final BiFunction<StandardSubjectBuilder, ? super T, ? extends S> valueSubjectCreator;
 
-  public static <S extends Subject<S, ? super T>, T> OptionalSubject<S, T> assertThat(
+  // TODO(aliceks): Remove when all relevant usages are adapted to new check()/factory approach.
+  public static <S extends Subject<S, T>, T> OptionalSubject<S, T> assertThat(
       Optional<T> optional, Function<? super T, ? extends S> elementAssertThatFunction) {
-    OptionalSubjectFactory<S, T> optionalSubjectFactory =
+    Subject.Factory<S, T> valueSubjectFactory =
-        new OptionalSubjectFactory<>(elementAssertThatFunction);
+        (metadata, value) -> elementAssertThatFunction.apply(value);
-    return assertAbout(optionalSubjectFactory).that(optional);
+    return assertThat(optional, valueSubjectFactory);
+  }
+
+  public static <S extends Subject<S, T>, T> OptionalSubject<S, T> assertThat(
+      Optional<T> optional, Subject.Factory<S, T> valueSubjectFactory) {
+    return assertAbout(optionals()).thatCustom(optional, valueSubjectFactory);
   }
 
   public static OptionalSubject<DefaultSubject, ?> assertThat(Optional<?> optional) {
-    // Unfortunately, we need to cast to DefaultSubject as Truth.assertThat()
+    // Unfortunately, we need to cast to DefaultSubject as StandardSubjectBuilder#that
     // only returns Subject<DefaultSubject, Object>. There shouldn't be a way
     // for that method not to return a DefaultSubject because the generic type
     // definitions of a Subject are quite strict.
-    Function<Object, DefaultSubject> valueAssertThatFunction =
+    return assertAbout(optionals())
-        value -> (DefaultSubject) Truth.assertThat(value);
+        .that(optional, (builder, value) -> (DefaultSubject) builder.that(value));
-    return assertThat(optional, valueAssertThatFunction);
+  }
+
+  public static CustomSubjectBuilder.Factory<OptionalSubjectBuilder> optionals() {
+    return OptionalSubjectBuilder::new;
   }
 
   private OptionalSubject(
       FailureMetadata failureMetadata,
       Optional<T> optional,
-      Function<? super T, ? extends S> valueAssertThatFunction) {
+      BiFunction<StandardSubjectBuilder, ? super T, ? extends S> valueSubjectCreator) {
     super(failureMetadata, optional);
-    this.valueAssertThatFunction = valueAssertThatFunction;
+    this.valueSubjectCreator = valueSubjectCreator;
   }
 
   public void isPresent() {
@@ -78,22 +89,28 @@ public class OptionalSubject<S extends Subject<S, ? super T>, T>
     isNotNull();
     isPresent();
     Optional<T> optional = actual();
-    return valueAssertThatFunction.apply(optional.get());
+    return valueSubjectCreator.apply(check("value()"), optional.get());
   }
 
-  private static class OptionalSubjectFactory<S extends Subject<S, ? super T>, T>
+  public static class OptionalSubjectBuilder extends CustomSubjectBuilder {
-      implements Subject.Factory<OptionalSubject<S, T>, Optional<T>> {
 
-    private Function<? super T, ? extends S> valueAssertThatFunction;
+    OptionalSubjectBuilder(FailureMetadata failureMetadata) {
-
+      super(failureMetadata);
-    OptionalSubjectFactory(Function<? super T, ? extends S> valueAssertThatFunction) {
-      this.valueAssertThatFunction = valueAssertThatFunction;
     }
 
-    @Override
+    public <S extends Subject<S, T>, T> OptionalSubject<S, T> thatCustom(
-    public OptionalSubject<S, T> createSubject(
+        Optional<T> optional, Subject.Factory<S, T> valueSubjectFactory) {
-        FailureMetadata failureMetadata, Optional<T> optional) {
+      return that(optional, (builder, value) -> builder.about(valueSubjectFactory).that(value));
-      return new OptionalSubject<>(failureMetadata, optional, valueAssertThatFunction);
+    }
+
+    public OptionalSubject<DefaultSubject, ?> that(Optional<?> optional) {
+      return that(optional, (builder, value) -> (DefaultSubject) builder.that(value));
+    }
+
+    public <S extends Subject<S, ? super T>, T> OptionalSubject<S, T> that(
+        Optional<T> optional,
+        BiFunction<StandardSubjectBuilder, ? super T, ? extends S> valueSubjectCreator) {
+      return new OptionalSubject<>(metadata(), optional, valueSubjectCreator);
     }
   }
 }

javatests/com/google/gerrit/acceptance/api/group/GroupIndexerIT.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.acceptance.api.group;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static com.google.gerrit.server.group.testing.InternalGroupSubject.internalGroups;
 import static com.google.gerrit.truth.ListSubject.assertThat;
 import static com.google.gerrit.truth.OptionalSubject.assertThat;
 
@@ -163,11 +164,11 @@ public class GroupIndexerIT {
 
   private static OptionalSubject<InternalGroupSubject, InternalGroup> assertThatGroup(
       Optional<InternalGroup> updatedGroup) {
-    return assertThat(updatedGroup, InternalGroupSubject::assertThat);
+    return assertThat(updatedGroup, internalGroups());
   }
 
   private static ListSubject<InternalGroupSubject, InternalGroup> assertThatGroups(
       List<InternalGroup> parentGroups) {
-    return assertThat(parentGroups, InternalGroupSubject::assertThat);
+    return assertThat(parentGroups, internalGroups());
   }
 }

javatests/com/google/gerrit/server/edit/tree/ChangeFileContentModificationSubject.java

@@ -20,7 +20,6 @@ import com.google.common.io.CharStreams;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.common.truth.Truth;
 import com.google.gerrit.extensions.restapi.RawInput;
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -41,16 +40,16 @@ public class ChangeFileContentModificationSubject
 
   public StringSubject filePath() {
     isNotNull();
-    return Truth.assertThat(actual().getFilePath()).named("filePath");
+    return check("filePath()").that(actual().getFilePath());
   }
 
   public StringSubject newContent() throws IOException {
     isNotNull();
     RawInput newContent = actual().getNewContent();
-    Truth.assertThat(newContent).named("newContent").isNotNull();
+    check("newContent()").that(newContent).isNotNull();
     String contentString =
         CharStreams.toString(
             new InputStreamReader(newContent.getInputStream(), StandardCharsets.UTF_8));
-    return Truth.assertThat(contentString).named("newContent");
+    return check("newContent()").that(contentString);
   }
 }

javatests/com/google/gerrit/server/edit/tree/TreeModificationSubject.java

@@ -24,12 +24,17 @@ import java.util.List;
 public class TreeModificationSubject extends Subject<TreeModificationSubject, TreeModification> {
 
   public static TreeModificationSubject assertThat(TreeModification treeModification) {
-    return assertAbout(TreeModificationSubject::new).that(treeModification);
+    return assertAbout(treeModifications()).that(treeModification);
+  }
+
+  private static Factory<TreeModificationSubject, TreeModification> treeModifications() {
+    return TreeModificationSubject::new;
   }
 
   public static ListSubject<TreeModificationSubject, TreeModification> assertThatList(
       List<TreeModification> treeModifications) {
-    return ListSubject.assertThat(treeModifications, TreeModificationSubject::assertThat)
+    return assertAbout(ListSubject.elements())
+        .thatCustom(treeModifications, treeModifications())
         .named("treeModifications");
   }
 

javatests/com/google/gerrit/server/group/db/GroupConfigTest.java

@@ -16,6 +16,7 @@ package com.google.gerrit.server.group.db;
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
+import static com.google.gerrit.server.group.testing.InternalGroupSubject.internalGroups;
 import static com.google.gerrit.truth.OptionalSubject.assertThat;
 import static org.hamcrest.CoreMatchers.instanceOf;
 
@@ -1673,6 +1674,6 @@ public class GroupConfigTest extends GerritBaseTests {
 
   private static OptionalSubject<InternalGroupSubject, InternalGroup> assertThatGroup(
       Optional<InternalGroup> loadedGroup) {
-    return assertThat(loadedGroup, InternalGroupSubject::assertThat);
+    return assertThat(loadedGroup, internalGroups());
   }
 }

javatests/com/google/gerrit/server/group/db/GroupNameNotesTest.java

@@ -16,7 +16,9 @@ package com.google.gerrit.server.group.db;
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assert_;
+import static com.google.gerrit.common.data.testing.GroupReferenceSubject.groupReferences;
 import static com.google.gerrit.extensions.common.testing.CommitInfoSubject.assertThat;
+import static com.google.gerrit.extensions.common.testing.CommitInfoSubject.commits;
 import static com.google.gerrit.reviewdb.client.RefNames.REFS_GROUPNAMES;
 import static com.google.gerrit.truth.OptionalSubject.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
@@ -584,11 +586,11 @@ public class GroupNameNotesTest extends GerritBaseTests {
 
   private static OptionalSubject<GroupReferenceSubject, GroupReference> assertThatGroup(
       Optional<GroupReference> group) {
-    return assertThat(group, GroupReferenceSubject::assertThat);
+    return assertThat(group, groupReferences());
   }
 
   private static ListSubject<CommitInfoSubject, CommitInfo> assertThatCommits(
       List<CommitInfo> commits) {
-    return ListSubject.assertThat(commits, CommitInfoSubject::assertThat);
+    return ListSubject.assertThat(commits, commits());
   }
 }