#patch: Enable snapshot-testing in a superclass

Tests can now use `Expect` defined in a superclass

Author: NicklasWallgren

java-snapshot-testing-core/src/main/java/au/com/origin/snapshots/utils/ReflectionUtils.java

@@ -0,0 +1,48 @@
+package au.com.origin.snapshots.utils;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.Optional;
+import java.util.function.Predicate;
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class ReflectionUtils {
+
+  /**
+   * Find {@link Field} by given predicate.
+   *
+   * <p>Invoke the given predicate on all fields in the target class, going up the class hierarchy
+   * to get all declared fields.
+   *
+   * @param clazz the target class to analyze
+   * @param predicate the predicate
+   * @return the field or empty optional
+   */
+  public static Optional<Field> findFieldByPredicate(
+      final Class<?> clazz, final Predicate<Field> predicate) {
+    Class<?> targetClass = clazz;
+
+    do {
+      final Field[] fields = targetClass.getDeclaredFields();
+      for (final Field field : fields) {
+        if (!predicate.test(field)) {
+          continue;
+        }
+        return Optional.of(field);
+      }
+      targetClass = targetClass.getSuperclass();
+    } while (targetClass != null && targetClass != Object.class);
+
+    return Optional.empty();
+  }
+
+  public static void makeAccessible(final Field field) {
+    if ((!Modifier.isPublic(field.getModifiers())
+            || !Modifier.isPublic(field.getDeclaringClass().getModifiers())
+            || Modifier.isFinal(field.getModifiers()))
+        && !field.isAccessible()) {
+      field.setAccessible(true);
+    }
+  }
+}

java-snapshot-testing-core/src/test/java/au/com/origin/snapshots/SnapshotHeaders.java

@@ -55,5 +55,5 @@ public Snapshot apply(Object object, SnapshotSerializerContext snapshotSerialize
       snapshotSerializerContext.getHeader().put("custom2", "anything2");
       return super.apply(object, snapshotSerializerContext);
     }
-  };
+  }
 }

java-snapshot-testing-junit4/src/main/java/au/com/origin/snapshots/junit4/SharedSnapshotHelpers.java

@@ -4,6 +4,7 @@
 import au.com.origin.snapshots.config.PropertyResolvingSnapshotConfig;
 import au.com.origin.snapshots.config.SnapshotConfig;
 import au.com.origin.snapshots.config.SnapshotConfigInjector;
+import au.com.origin.snapshots.utils.ReflectionUtils;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import org.junit.runner.Description;
@@ -14,13 +15,13 @@ class SharedSnapshotHelpers implements SnapshotConfigInjector {
 
   public void injectExpectInstanceVariable(
       SnapshotVerifier snapshotVerifier, Method testMethod, Object testInstance) {
-    Arrays.stream(testInstance.getClass().getDeclaredFields())
-        .filter(it -> it.getType() == Expect.class)
-        .findFirst()
+
+    ReflectionUtils.findFieldByPredicate(
+            testInstance.getClass(), (field) -> field.getType() == Expect.class)
         .ifPresent(
-            field -> {
+            (field) -> {
               Expect expect = Expect.of(snapshotVerifier, testMethod);
-              field.setAccessible(true);
+              ReflectionUtils.makeAccessible(field);
               try {
                 field.set(testInstance, expect);
               } catch (IllegalAccessException e) {

java-snapshot-testing-junit4/src/test/java/au/com/origin/snapshots/BaseClassTest.java

@@ -0,0 +1,23 @@
+package au.com.origin.snapshots;
+
+import au.com.origin.snapshots.junit4.SnapshotRunner;
+import org.junit.Test;
+import org.junit.experimental.runners.Enclosed;
+import org.junit.runner.RunWith;
+
+@RunWith(Enclosed.class)
+public class BaseClassTest {
+
+  static class TestBase {
+    Expect expect;
+  }
+
+  @RunWith(SnapshotRunner.class)
+  public static class NestedClass extends TestBase {
+
+    @Test
+    public void helloWorldTest() {
+      expect.toMatchSnapshot("Hello World");
+    }
+  }
+}

java-snapshot-testing-junit4/src/test/java/au/com/origin/snapshots/__snapshots__/BaseClassTest$NestedClass.snap

@@ -0,0 +1,3 @@
+au.com.origin.snapshots.BaseClassTest$NestedClass.helloWorldTest=[
+Hello World
+]

java-snapshot-testing-junit5/src/main/java/au/com/origin/snapshots/junit5/SnapshotExtension.java

@@ -7,10 +7,16 @@
 import au.com.origin.snapshots.config.SnapshotConfigInjector;
 import au.com.origin.snapshots.exceptions.SnapshotMatchException;
 import au.com.origin.snapshots.logging.LoggingHelper;
+import au.com.origin.snapshots.utils.ReflectionUtils;
 import java.lang.reflect.Field;
-import java.util.Arrays;
 import lombok.extern.slf4j.Slf4j;
-import org.junit.jupiter.api.extension.*;
+import org.junit.jupiter.api.extension.AfterAllCallback;
+import org.junit.jupiter.api.extension.BeforeAllCallback;
+import org.junit.jupiter.api.extension.BeforeEachCallback;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolutionException;
+import org.junit.jupiter.api.extension.ParameterResolver;
 import org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor;
 import org.junit.jupiter.engine.descriptor.ClassTestDescriptor;
 
@@ -104,13 +110,12 @@ public Object resolveParameter(
   @Override
   public void beforeEach(ExtensionContext context) {
     if (context.getTestInstance().isPresent() && context.getTestMethod().isPresent()) {
-      Arrays.stream(context.getTestClass().get().getDeclaredFields())
-          .filter(it -> it.getType() == Expect.class)
-          .findFirst()
+      ReflectionUtils.findFieldByPredicate(
+              context.getTestClass().get(), (field) -> field.getType() == Expect.class)
           .ifPresent(
-              field -> {
+              (field) -> {
                 Expect expect = Expect.of(snapshotVerifier, context.getTestMethod().get());
-                field.setAccessible(true);
+                ReflectionUtils.makeAccessible(field);
                 try {
                   field.set(context.getTestInstance().get(), expect);
                 } catch (IllegalAccessException e) {

java-snapshot-testing-junit5/src/test/java/au/com/origin/snapshots/BaseClassTest.java

@@ -0,0 +1,24 @@
+package au.com.origin.snapshots;
+
+import au.com.origin.snapshots.junit5.SnapshotExtension;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+@ExtendWith({SnapshotExtension.class})
+public class BaseClassTest {
+
+  class TestBase {
+    Expect expect;
+  }
+
+  @Nested
+  @ExtendWith(SnapshotExtension.class)
+  class NestedClass extends TestBase {
+
+    @Test
+    public void helloWorldTest() {
+      expect.toMatchSnapshot("Hello World");
+    }
+  }
+}

java-snapshot-testing-junit5/src/test/java/au/com/origin/snapshots/__snapshots__/BaseClassTest$NestedClass.snap

@@ -0,0 +1,3 @@
+au.com.origin.snapshots.BaseClassTest$NestedClass.helloWorldTest=[
+Hello World
+]

java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotMethodInterceptor.groovy

@@ -1,12 +1,11 @@
 package au.com.origin.snapshots.spock
 
 import au.com.origin.snapshots.Expect
+import au.com.origin.snapshots.utils.ReflectionUtils
 import au.com.origin.snapshots.SnapshotVerifier
 import au.com.origin.snapshots.logging.LoggingHelper
-import lombok.extern.slf4j.Slf4j
 import org.slf4j.LoggerFactory
 import org.spockframework.runtime.extension.AbstractMethodInterceptor
-import org.spockframework.runtime.extension.IMethodInterceptor
 import org.spockframework.runtime.extension.IMethodInvocation
 
 import java.lang.reflect.Method
@@ -40,13 +39,16 @@ class SnapshotMethodInterceptor extends AbstractMethodInterceptor {
     }
 
     private void updateInstanceVariable(Object testInstance, Method testMethod) {
-        testInstance.class.declaredFields
-            .find { it.getType() == Expect.class }
-            ?.with {
-                Expect expect = Expect.of(snapshotVerifier, testMethod)
-                it.setAccessible(true)
-                it.set(testInstance, expect)
-            }
+        ReflectionUtils.findFieldByPredicate(testInstance.class, { field -> field.getType() == Expect.class })
+            .ifPresent({ field ->
+                Expect expect = Expect.of(snapshotVerifier, testMethod);
+                ReflectionUtils.makeAccessible(field);
+                try {
+                    field.set(testInstance, expect);
+                } catch (IllegalAccessException e) {
+                    throw new RuntimeException(e);
+                }
+            });
     }
 
     @Override

java-snapshot-testing-spock/src/test/groovy/au/com/origin/snapshots/SpecificationBase.groovy

@@ -0,0 +1,10 @@
+package au.com.origin.snapshots
+
+import org.junit.runner.RunWith
+import org.spockframework.runtime.Sputnik
+import spock.lang.Specification
+
+@RunWith(Sputnik.class)
+class SpecificationBase extends Specification {
+    Expect expect;
+}