1 files changed, 140 insertions, 0 deletions
diff --git a/junit5/src/main/java/com/google/testing/junit/testparameterinjector/junit5/TestParameterInjectorExtension.java b/junit5/src/main/java/com/google/testing/junit/testparameterinjector/junit5/TestParameterInjectorExtension.java
new file mode 100644
index 0000000..6d6aa51
--- /dev/null
+++ b/junit5/src/main/java/com/google/testing/junit/testparameterinjector/junit5/TestParameterInjectorExtension.java
@@ -0,0 +1,140 @@
+/*
+ * Copyright 2021 Google Inc.
+ *
+ * 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.testing.junit.testparameterinjector.junit5;
+
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.collect.Iterables.getOnlyElement;
+
+import com.google.auto.value.AutoValue;
+import com.google.auto.value.extension.memoized.Memoized;
+import com.google.common.collect.ImmutableList;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.extension.Extension;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolver;
+import org.junit.jupiter.api.extension.TestInstancePostProcessor;
+import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
+import org.junit.jupiter.api.extension.TestTemplateInvocationContextProvider;
+
+/** Implements the TestParameterInjector logic for JUnit5 (Jupiter). */
+class TestParameterInjectorExtension implements TestTemplateInvocationContextProvider {
+
+  private static final TestMethodProcessorList testMethodProcessors =
+      TestMethodProcessorList.createNewParameterizedProcessors();
+
+  @Override
+  public boolean supportsTestTemplate(ExtensionContext context) {
+    return true;
+  }
+
+  @Override
+  public Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(
+      ExtensionContext extensionContext) {
+    validateTestMethodAndConstructor(
+        extensionContext.getRequiredTestMethod(), extensionContext.getRequiredTestClass());
+    List<TestInfo> testInfos =
+        testMethodProcessors.calculateTestInfos(
+            extensionContext.getRequiredTestMethod(), extensionContext.getRequiredTestClass());
+
+    return testInfos.stream().map(CustomInvocationContext::of);
+  }
+
+  private void validateTestMethodAndConstructor(Method testMethod, Class<?> testClass) {
+    checkState(
+        testClass.getDeclaredConstructors().length == 1,
+        "Only a single constructor is allowed, but found %s in %s",
+        testClass.getDeclaredConstructors().length,
+        testClass.getSimpleName());
+    Constructor<?> constructor =
+        getOnlyElement(ImmutableList.copyOf(testClass.getDeclaredConstructors()));
+
+    testMethodProcessors.validateConstructor(constructor).assertValid();
+
+    testMethodProcessors.validateTestMethod(testMethod, testClass).assertValid();
+
+    checkState(
+        testMethod.getAnnotation(TestParameterInjectorTest.class) != null,
+        "Each test method handled by this extension should be annotated with"
+            + " @TestParameterInjectorTest");
+  }
+
+  @AutoValue
+  abstract static class CustomInvocationContext implements TestTemplateInvocationContext {
+
+    abstract TestInfo testInfo();
+
+    @Memoized
+    List<Object> getConstructorParameters() {
+      Constructor<?> constructor =
+          getOnlyElement(ImmutableList.copyOf(testInfo().getTestClass().getDeclaredConstructors()));
+
+      return testMethodProcessors.getConstructorParameters(constructor, testInfo());
+    }
+
+    @Memoized
+    List<Object> getTestMethodParameters() {
+      return testMethodProcessors.getTestMethodParameters(testInfo());
+    }
+
+    static CustomInvocationContext of(TestInfo testInfo) {
+      return new AutoValue_TestParameterInjectorExtension_CustomInvocationContext(testInfo);
+    }
+
+    @Override
+    public String getDisplayName(int invocationIndex) {
+      return testInfo().getName();
+    }
+
+    @Override
+    public List<Extension> getAdditionalExtensions() {
+      return ImmutableList.of(new CustomAdditionalExtension());
+    }
+
+    class CustomAdditionalExtension implements ParameterResolver, TestInstancePostProcessor {
+
+      @Override
+      public boolean supportsParameter(
+          ParameterContext parameterContext, ExtensionContext extensionContext) {
+        if (parameterContext.getDeclaringExecutable() instanceof Constructor) {
+          return true;
+        } else {
+          return parameterContext
+              .getDeclaringExecutable()
+              .isAnnotationPresent(TestParameterInjectorTest.class);
+        }
+      }
+
+      @Override
+      public Object resolveParameter(
+          ParameterContext parameterContext, ExtensionContext extensionContext) {
+        if (parameterContext.getDeclaringExecutable() instanceof Constructor) {
+          return getConstructorParameters().get(parameterContext.getIndex());
+        } else {
+          return getTestMethodParameters().get(parameterContext.getIndex());
+        }
+      }
+
+      @Override
+      public void postProcessTestInstance(Object testInstance, ExtensionContext extensionContext)
+          throws Exception {
+        testMethodProcessors.postProcessTestInstance(testInstance, testInfo());
+      }
+    }
+  }
+}