Add simple test of index-agnostic QueryBuilder

Change-Id: I570410f5e32a7306017330c7455d5d19bcc530eb

javatests/com/google/gerrit/index/query/QueryBuilderTest.java

@@ -0,0 +1,90 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index.query;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.truth.ThrowableSubject;
+import com.google.gerrit.testing.GerritBaseTests;
+import java.util.Collection;
+import java.util.Objects;
+import org.junit.Test;
+
+public class QueryBuilderTest extends GerritBaseTests {
+  private static class TestPredicate extends Predicate<Object> {
+    private final String field;
+    private final String value;
+
+    TestPredicate(String field, String value) {
+      this.field = field;
+      this.value = value;
+    }
+
+    @Override
+    public Predicate<Object> copy(Collection<? extends Predicate<Object>> children) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(field, value);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (!(o instanceof TestPredicate)) {
+        return false;
+      }
+      TestPredicate p = (TestPredicate) o;
+      return Objects.equals(field, p.field) && Objects.equals(value, p.value);
+    }
+  }
+
+  private static class TestQueryBuilder extends QueryBuilder<Object> {
+    TestQueryBuilder() {
+      super(new QueryBuilder.Definition<>(TestQueryBuilder.class));
+    }
+
+    @Operator
+    public Predicate<Object> a(String value) {
+      return new TestPredicate("a", value);
+    }
+  }
+
+  @Test
+  public void fieldNameAndValue() throws Exception {
+    assertThat(parse("a:foo")).isEqualTo(new TestPredicate("a", "foo"));
+  }
+
+  @Test
+  public void fieldWithParenthesizedValues() throws Exception {
+    assertThatParseException("a:(foo bar)")
+        .hasMessageThat()
+        .isEqualTo("line 1:2 no viable alternative at input '('");
+  }
+
+  private static Predicate<Object> parse(String query) throws Exception {
+    return new TestQueryBuilder().parse(query);
+  }
+
+  private static ThrowableSubject assertThatParseException(String query) {
+    try {
+      new TestQueryBuilder().parse(query);
+      throw new AssertionError("expected QueryParseException for " + query);
+    } catch (QueryParseException e) {
+      return assertThat(e);
+    }
+  }
+}