Add support for dynamic config suites

By annotating methods with @ConfigSuite.Config config suites with
different configurations can be defined. However the set of config
suites is static, since one method per config suite must be defined.
Add a new @ConfigSuite.Configs annotation on a method that returns
Map<String, Config> to support dynamic config suites. The map keys
define the test suite names, while the values define the
configurations for the test suites. E.g.:

  @ConfigSuite.Configs
  public static Mapi<String, Config> configs() {
    Config cfgA = new Config();
    cfgA.setString("gerrit", null, "testValue", "a");
    Config cfgB = new Config();
    cfgB.setString("gerrit", null, "testValue", "b");
    return ImmutableMap.of("testWithValueA", cfgA, "testWithValueB", cfgB);
  }

In the follow-up changes this new annotation will be used to execute
query tests against old index versions.

Change-Id: I47e182bac6485457467f1d6573aca54ebf0ea9de
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-server/src/test/java/com/google/gerrit/testutil/ConfigSuite.java

@@ -18,8 +18,10 @@ import static com.google.common.base.Preconditions.checkArgument;
 import static java.lang.annotation.ElementType.FIELD;
 import static java.lang.annotation.ElementType.METHOD;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
+import static java.util.stream.Collectors.toSet;
 
 import com.google.common.base.MoreObjects;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import java.lang.annotation.Annotation;
@@ -29,7 +31,10 @@ import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
 import java.util.List;
+import java.util.Map;
 import org.junit.runner.Runner;
 import org.junit.runners.BlockJUnit4ClassRunner;
 import org.junit.runners.Suite;
@@ -80,6 +85,21 @@ import org.junit.runners.model.InitializationError;
  * Additionally, config values used by <strong>default</strong> can be set in a method annotated
  * with {@code @ConfigSuite.Default}.
  *
+ * <p>In addition groups of tests for different configurations can be defined by annotating a method
+ * that returns a Map&lt;String, Config&gt; with {@link Configs}. The map keys define the test suite
+ * names, while the values define the configurations for the test suites.
+ *
+ * <pre>
+ * {@literal @}ConfigSuite.Configs
+ * public static Map&lt;String, Config&gt; configs() {
+ *   Config cfgA = new Config();
+ *   cfgA.setString("gerrit", null, "testValue", "a");
+ *   Config cfgB = new Config();
+ *   cfgB.setString("gerrit", null, "testValue", "b");
+ *   return ImmutableMap.of("testWithValueA", cfgA, "testWithValueB", cfgB);
+ * }
+ * </pre>
+ *
  * <p>The name of the config method corresponding to the currently-running test can be stored in a
  * field annotated with {@code @ConfigSuite.Name}.
  */
@@ -94,6 +114,10 @@ public class ConfigSuite extends Suite {
   @Retention(RUNTIME)
   public static @interface Config {}
 
+  @Target({METHOD})
+  @Retention(RUNTIME)
+  public static @interface Configs {}
+
   @Target({FIELD})
   @Retention(RUNTIME)
   public static @interface Parameter {}
@@ -103,25 +127,29 @@ public class ConfigSuite extends Suite {
   public static @interface Name {}
 
   private static class ConfigRunner extends BlockJUnit4ClassRunner {
-    private final Method configMethod;
+    private final org.eclipse.jgit.lib.Config cfg;
     private final Field parameterField;
     private final Field nameField;
     private final String name;
 
     private ConfigRunner(
-        Class<?> clazz, Field parameterField, Field nameField, String name, Method configMethod)
+        Class<?> clazz,
+        Field parameterField,
+        Field nameField,
+        String name,
+        org.eclipse.jgit.lib.Config cfg)
         throws InitializationError {
       super(clazz);
       this.parameterField = parameterField;
       this.nameField = nameField;
       this.name = name;
-      this.configMethod = configMethod;
+      this.cfg = cfg;
     }
 
     @Override
     public Object createTest() throws Exception {
       Object test = getTestClass().getJavaClass().newInstance();
-      parameterField.set(test, callConfigMethod(configMethod));
+      parameterField.set(test, new org.eclipse.jgit.lib.Config(cfg));
       if (nameField != null) {
         nameField.set(test, name);
       }
@@ -143,14 +171,23 @@ public class ConfigSuite extends Suite {
   private static List<Runner> runnersFor(Class<?> clazz) {
     Method defaultConfig = getDefaultConfig(clazz);
     List<Method> configs = getConfigs(clazz);
+    Map<String, org.eclipse.jgit.lib.Config> configMap =
+        callConfigMapMethod(getConfigMap(clazz), configs);
+
     Field parameterField = getOnlyField(clazz, Parameter.class);
     checkArgument(parameterField != null, "No @ConfigSuite.Field found");
     Field nameField = getOnlyField(clazz, Name.class);
     List<Runner> result = Lists.newArrayListWithCapacity(configs.size() + 1);
     try {
-      result.add(new ConfigRunner(clazz, parameterField, nameField, null, defaultConfig));
+      result.add(
+          new ConfigRunner(
+              clazz, parameterField, nameField, null, callConfigMethod(defaultConfig)));
       for (Method m : configs) {
-        result.add(new ConfigRunner(clazz, parameterField, nameField, m.getName(), m));
+        result.add(
+            new ConfigRunner(clazz, parameterField, nameField, m.getName(), callConfigMethod(m)));
+      }
+      for (Map.Entry<String, org.eclipse.jgit.lib.Config> e : configMap.entrySet()) {
+        result.add(new ConfigRunner(clazz, parameterField, nameField, e.getKey(), e.getValue()));
       }
       return result;
     } catch (InitializationError e) {
@@ -163,15 +200,20 @@ public class ConfigSuite extends Suite {
   }
 
   private static Method getDefaultConfig(Class<?> clazz) {
+    return getAnnotatedMethod(clazz, Default.class);
+  }
+
+  private static Method getConfigMap(Class<?> clazz) {
+    return getAnnotatedMethod(clazz, Configs.class);
+  }
+
+  private static <T extends Annotation> Method getAnnotatedMethod(
+      Class<?> clazz, Class<T> annotationClass) {
     Method result = null;
     for (Method m : clazz.getMethods()) {
-      Default ann = m.getAnnotation(Default.class);
+      T ann = m.getAnnotation(annotationClass);
       if (ann != null) {
-        checkArgument(
+        checkArgument(result == null, "Multiple methods annotated with %s: %s, %s", ann, result, m);
-            result == null,
-            "Multiple methods annotated with @ConfigSuite.Method: %s, %s",
-            result,
-            m);
         result = m;
       }
     }
@@ -183,8 +225,7 @@ public class ConfigSuite extends Suite {
     for (Method m : clazz.getMethods()) {
       Config ann = m.getAnnotation(Config.class);
       if (ann != null) {
-        checkArgument(
+        checkArgument(!m.getName().equals(DEFAULT), "%s cannot be named %s", ann, DEFAULT);
-            !m.getName().equals(DEFAULT), "@ConfigSuite.Config cannot be named %s", DEFAULT);
         result.add(m);
       }
     }
@@ -208,6 +249,45 @@ public class ConfigSuite extends Suite {
     }
   }
 
+  private static Map<String, org.eclipse.jgit.lib.Config> callConfigMapMethod(
+      Method m, List<Method> configs) {
+    if (m == null) {
+      return ImmutableMap.of();
+    }
+    checkArgument(Map.class.isAssignableFrom(m.getReturnType()), "%s must return Map", m);
+    Type[] types = ((ParameterizedType) m.getGenericReturnType()).getActualTypeArguments();
+    checkArgument(
+        String.class.isAssignableFrom((Class<?>) types[0]),
+        "The map returned by %s must have String as key",
+        m);
+    checkArgument(
+        org.eclipse.jgit.lib.Config.class.isAssignableFrom((Class<?>) types[1]),
+        "The map returned by %s must have Config as value",
+        m);
+    checkArgument((m.getModifiers() & Modifier.STATIC) != 0, "%s must be static", m);
+    checkArgument(m.getParameterTypes().length == 0, "%s must take no parameters", m);
+    try {
+      @SuppressWarnings("unchecked")
+      Map<String, org.eclipse.jgit.lib.Config> configMap =
+          (Map<String, org.eclipse.jgit.lib.Config>) m.invoke(null);
+      checkArgument(
+          !configMap.containsKey(DEFAULT),
+          "The map returned by %s cannot contain key %s (duplicate test suite name)",
+          m,
+          DEFAULT);
+      for (String name : configs.stream().map(cm -> cm.getName()).collect(toSet())) {
+        checkArgument(
+            !configMap.containsKey(name),
+            "The map returned by %s cannot contain key %s (duplicate test suite name)",
+            m,
+            name);
+      }
+      return configMap;
+    } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
+      throw new IllegalArgumentException(e);
+    }
+  }
+
   private static Field getOnlyField(Class<?> clazz, Class<? extends Annotation> ann) {
     List<Field> fields = Lists.newArrayListWithExpectedSize(1);
     for (Field f : clazz.getFields()) {