Cached injector for common modules

guice-extension/src/main/java/name/falgout/jeffrey/testing/junit/guice/GuiceExtension.java

@@ -2,6 +2,7 @@
 
 import static java.util.stream.Collectors.toSet;
 import static org.junit.platform.commons.support.AnnotationSupport.findRepeatableAnnotations;
+import static org.junit.platform.commons.support.AnnotationSupport.isAnnotated;
 
 import com.google.common.collect.Iterables;
 import com.google.common.reflect.TypeToken;
@@ -25,6 +26,8 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.stream.Stream;
 import javax.inject.Qualifier;
 import org.junit.jupiter.api.extension.ExtensionContext;
@@ -39,6 +42,8 @@ public final class GuiceExtension implements TestInstancePostProcessor, Paramete
   private static final Namespace NAMESPACE =
       Namespace.create("name", "falgout", "jeffrey", "testing", "junit", "guice");
 
+  private static final ConcurrentMap<Set<? extends Class<?>>, Injector> INJECTOR_CACHE = new ConcurrentHashMap<>();
+
   public GuiceExtension() {}
 
   @Override
@@ -59,16 +64,22 @@ private static Optional<Injector> getOrCreateInjector(ExtensionContext context)
     if (!context.getElement().isPresent()) {
       return Optional.empty();
     }
-
     AnnotatedElement element = context.getElement().get();
     Store store = context.getStore(NAMESPACE);
-
     Injector injector = store.get(element, Injector.class);
+    boolean sharedInjector = isSharedInjector(context);
+    Set<Class<? extends Module>> moduleClasses = Collections.emptySet();
+    if (injector == null && sharedInjector) {
+      moduleClasses = getContextModuleTypes(context);
+      injector = INJECTOR_CACHE.get(moduleClasses);
+    }
     if (injector == null) {
       injector = createInjector(context);
       store.put(element, injector);
+      if (sharedInjector && !moduleClasses.isEmpty()) {
+        INJECTOR_CACHE.put(moduleClasses, injector);
+      }
     }
-
     return Optional.of(injector);
   }
 
@@ -79,12 +90,19 @@ private static Injector createInjector(ExtensionContext context)
       InvocationTargetException {
     Optional<Injector> parentInjector = getParentInjector(context);
     List<? extends Module> modules = getNewModules(context);
-
     return parentInjector
         .map(injector -> injector.createChildInjector(modules))
         .orElseGet(() -> Guice.createInjector(modules));
   }
 
+  private static boolean isSharedInjector(ExtensionContext context) {
+    if (!context.getElement().isPresent()) {
+      return false;
+    }
+    AnnotatedElement element = context.getElement().get();
+    return isAnnotated(element, SharedInjectors.class);
+  }
+
   private static Optional<Injector> getParentInjector(ExtensionContext context)
       throws NoSuchMethodException,
       InstantiationException,

guice-extension/src/main/java/name/falgout/jeffrey/testing/junit/guice/SharedInjectors.java

@@ -0,0 +1,20 @@
+package name.falgout.jeffrey.testing.junit.guice;
+
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+@Documented
+@Retention(RUNTIME)
+@Target({TYPE, METHOD})
+@Inherited
+@ExtendWith(GuiceExtension.class)
+public @interface SharedInjectors {
+}

guice-extension/src/test/java/name/falgout/jeffrey/testing/junit/guice/SharedInjectorsTest.java

@@ -0,0 +1,201 @@
+package name.falgout.jeffrey.testing.junit.guice;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.google.inject.AbstractModule;
+import com.google.inject.name.Names;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import javax.inject.Named;
+import name.falgout.jeffrey.testing.junit.guice.SharedInjectorsTest.OuterClassModule;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+@ExtendWith(GuiceExtension.class)
+@IncludeModule(OuterClassModule.class)
+@SharedInjectors
+class SharedInjectorsTest {
+
+  @Test
+  @IncludeModule(TestCaseModule.class)
+  @SharedInjectors
+  void test1(@Named("base") String base, @Named("test") String test) {
+    assertEquals("base", base);
+    assertEquals("test", test);
+  }
+
+  @Test
+  @SharedInjectors
+  @IncludeModule(OuterSharedClassModule.class)
+  void testCase2(int value) {
+    assertEquals(1, value);
+  }
+
+
+  @IncludeModule(InnerClassModule.class)
+  @Nested
+  class InnerClass {
+
+    @SharedInjectors
+    @IncludeModule(TestCaseModule.class)
+    @Test
+    void test1(@Named("base") String base,
+        @Named("inner") String inner,
+        @Named("test") String test) {
+      assertEquals("base", base);
+      assertEquals("test", test);
+      assertEquals("inner", inner);
+    }
+  }
+
+  @Nested
+  @IncludeModule(CachedModule.class)
+  @SharedInjectors
+  class FirstCachedInjectorTest {
+
+    @Test
+    void firstTest(long i) {
+      assertEquals(1, i);
+    }
+
+    @Test
+    void secondTest(long i) {
+      assertEquals(1, i);
+    }
+  }
+
+  @Nested
+  @IncludeModule(CachedModule.class)
+  @SharedInjectors
+  class SecondCachedInjectorTest {
+
+    @Test
+    void firstTest(long i) {
+      assertEquals(1, i);
+    }
+
+    @Test
+    void secondTest(long i) {
+      assertEquals(1, i);
+    }
+  }
+
+  @Nested
+  @IncludeModule(NonCachedModule.class)
+  class FirstNonCachedInjectorTest {
+
+    @Test
+    void test(long i) {
+      long expectedValue = NonCachedModule.SECOND_EXECUTED.get() ? 2 : 1;
+      assertEquals(expectedValue, i);
+      NonCachedModule.FIRST_EXECUTED.set(true);
+    }
+  }
+
+  @Nested
+  @IncludeModule(NonCachedModule.class)
+  class SecondNonCachedInjectorTest {
+
+    @Test
+    void test(long i) {
+      long expectedValue = NonCachedModule.FIRST_EXECUTED.get() ? 2 : 1;
+      assertEquals(expectedValue, i);
+      NonCachedModule.SECOND_EXECUTED.set(true);
+    }
+  }
+
+  @IncludeModule(OuterSharedClassModule.class)
+  @SharedInjectors
+  @Nested
+  class OuterSharedClass {
+
+    @IncludeModule(ExtraModule.class)
+    @Test
+    void testCase1(int value, @Named("extra") int extra) {
+      assertEquals(1, value);
+      assertEquals(ExtraModule.EXTRA2_EXECUTED.get() ? 2 : 1, extra);
+      ExtraModule.EXTRA1_EXECUTED.set(true);
+    }
+
+    @Test
+    @IncludeModule(ExtraModule.class)
+    void testCase2(int value, @Named("extra") int extra) {
+      assertEquals(1, value);
+      assertEquals(ExtraModule.EXTRA1_EXECUTED.get() ? 2 : 1, extra);
+      ExtraModule.EXTRA2_EXECUTED.set(true);
+    }
+  }
+
+  static class OuterSharedClassModule extends AbstractModule {
+
+    private final static AtomicInteger ATOMIC_INTEGER = new AtomicInteger(0);
+
+    @Override
+    protected void configure() {
+      int value = ATOMIC_INTEGER.incrementAndGet();
+      bind(int.class).toInstance(value);
+      assertEquals(1, value);
+    }
+  }
+
+  static class ExtraModule extends AbstractModule {
+
+    static final AtomicBoolean EXTRA1_EXECUTED = new AtomicBoolean(false);
+    static final AtomicBoolean EXTRA2_EXECUTED = new AtomicBoolean(false);
+    static final AtomicInteger INTEGER = new AtomicInteger(0);
+
+    @Override
+    protected void configure() {
+      bind(int.class).annotatedWith(Names.named("extra")).toInstance(INTEGER.incrementAndGet());
+    }
+  }
+
+  static class OuterClassModule extends AbstractModule {
+
+    @Override
+    protected void configure() {
+      bind(String.class).annotatedWith(Names.named("base")).toInstance("base");
+    }
+  }
+
+  static class InnerClassModule extends AbstractModule {
+
+    @Override
+    protected void configure() {
+      bind(String.class).annotatedWith(Names.named("inner")).toInstance("inner");
+    }
+  }
+
+  static class TestCaseModule extends AbstractModule {
+
+    @Override
+    protected void configure() {
+      bind(String.class).annotatedWith(Names.named("test")).toInstance("test");
+    }
+  }
+
+  static final class CachedModule extends AbstractModule {
+
+    static final AtomicLong ATOMIC_LONG = new AtomicLong(0);
+
+    @Override
+    protected void configure() {
+      bind(long.class).toInstance(ATOMIC_LONG.incrementAndGet());
+    }
+  }
+
+  static final class NonCachedModule extends AbstractModule {
+
+    static final AtomicLong ATOMIC_LONG = new AtomicLong(0);
+    //depend on which test executed first
+    static final AtomicBoolean FIRST_EXECUTED = new AtomicBoolean(false);
+    static final AtomicBoolean SECOND_EXECUTED = new AtomicBoolean(false);
+
+    @Override
+    protected void configure() {
+      bind(long.class).toInstance(ATOMIC_LONG.incrementAndGet());
+    }
+  }
+}