Make the failsToCompile() and compilesWithoutError() clauses report the files they generate on failure.

cgruber · cgruber · commit 7933bde65172 · 2014-07-17T13:46:01.000-07:00
------------- Created by MOE: http://code.google.com/p/moe-java MOE_MIGRATED_REVID=68173836
diff --git a/src/main/java/com/google/testing/compile/JavaSourcesSubject.java b/src/main/java/com/google/testing/compile/JavaSourcesSubject.java
@@ -16,6 +16,7 @@
 package com.google.testing.compile;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static javax.tools.JavaFileObject.Kind.CLASS;
 
 import com.google.common.base.Function;
 import com.google.common.base.Joiner;
@@ -28,6 +29,7 @@
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.io.ByteSource;
 import com.google.common.io.ByteStreams;
 import com.google.testing.compile.Compilation.Result;
 
@@ -92,14 +94,58 @@ private CompilationClause(Iterable<? extends Processor> processors) {
       this.processors = ImmutableSet.copyOf(processors);
     }
 
+    /** Returns a {@code String} report describing the contents of a given generated file. */
+    private String reportFileGenerated(JavaFileObject generatedFile) {
+      try {
+        StringBuilder entry =
+            new StringBuilder().append(String.format("\n%s:\n", generatedFile.toUri().getPath()));
+        if (generatedFile.getKind().equals(CLASS)) {
+          entry.append(String.format("[generated class file (%s bytes)]",
+                  ByteSource.wrap(ByteStreams.toByteArray(generatedFile.openInputStream()))
+                  .size()));
+        } else {
+          entry.append(generatedFile.getCharContent(true));
+        }
+        return entry.append("\n").toString();
+      } catch (IOException e) {
+        throw new IllegalStateException("Couldn't read from JavaFileObject when it was "
+            + "already in memory.", e);
+      }
+    }
+
+    /**
+     * Returns a {@code String} report describing what files were generated in the given
+     * {@link Compilation.Result}
+     */
+    private String reportFilesGenerated(Compilation.Result result) {
+      FluentIterable<JavaFileObject> generatedFiles =
+          FluentIterable.from(result.generatedSources());
+      StringBuilder message = new StringBuilder("\n\n");
+      if (generatedFiles.isEmpty()) {
+        return message.append("(No files were generated.)\n").toString();
+      } else {
+        message.append("Generated Files\n")
+            .append("===============\n");
+        for (JavaFileObject generatedFile : generatedFiles) {
+          message.append(reportFileGenerated(generatedFile));
+        }
+        return message.toString();
+      }
+    }
+
     @Override
     public SuccessfulCompilationClause compilesWithoutError() {
       Compilation.Result result = Compilation.compile(processors, getSubject());
       if (!result.successful()) {
         ImmutableList<Diagnostic<? extends JavaFileObject>> errors =
             result.diagnosticsByKind().get(Kind.ERROR);
         StringBuilder message = new StringBuilder("Compilation produced the following errors:\n");
-        Joiner.on('\n').appendTo(message, errors);
+        for (Diagnostic<? extends JavaFileObject> error : errors) {
+          message.append('\n');
+          message.append(error);
+        }
+        message.append('\n');
+        message.append(reportFilesGenerated(result));
         failureStrategy.fail(message.toString());
       }
       return new SuccessfulCompilationBuilder(result);
@@ -109,7 +155,11 @@ public SuccessfulCompilationClause compilesWithoutError() {
     public UnsuccessfulCompilationClause failsToCompile() {
       Result result = Compilation.compile(processors, getSubject());
       if (result.successful()) {
-        failureStrategy.fail("Compilation was expected to fail, but contained no errors");
+        String message = Joiner.on('\n').join(
+            "Compilation was expected to fail, but contained no errors.",
+            "",
+            reportFilesGenerated(result));
+        failureStrategy.fail(message);
       }
       return new UnsuccessfulCompilationBuilder(result);
     }
diff --git a/src/test/java/com/google/testing/compile/JavaSourcesSubjectFactoryTest.java b/src/test/java/com/google/testing/compile/JavaSourcesSubjectFactoryTest.java
@@ -76,6 +76,21 @@ public void compilesWithoutError() {
         .compilesWithoutError();
   }
 
+  @Test
+  public void compilesWithoutError_failureReportsFiles() {
+    try {
+      VERIFY.about(javaSource())
+          .that(JavaFileObjects.forResource(Resources.getResource("HelloWorld.java")))
+          .processedWith(new FailingGeneratingProcessor())
+          .compilesWithoutError();
+      fail();
+    } catch (VerificationException expected) {
+      ASSERT.that(expected.getMessage()).contains("Compilation produced the following errors:\n");
+      ASSERT.that(expected.getMessage()).contains(FailingGeneratingProcessor.GENERATED_CLASS_NAME);
+      ASSERT.that(expected.getMessage()).contains(FailingGeneratingProcessor.GENERATED_SOURCE);
+    }
+  }
+
   @Test
   public void compilesWithoutError_throws() {
     try {
@@ -85,6 +100,7 @@ public void compilesWithoutError_throws() {
       fail();
     } catch (VerificationException expected) {
       ASSERT.that(expected.getMessage()).startsWith("Compilation produced the following errors:\n");
+      ASSERT.that(expected.getMessage()).contains("No files were generated.");
     }
   }
 
@@ -124,8 +140,9 @@ public void failsToCompile_throws() {
           .failsToCompile();
       fail();
     } catch (VerificationException expected) {
-      ASSERT.that(expected.getMessage()).isEqualTo(
+      ASSERT.that(expected.getMessage()).startsWith(
           "Compilation was expected to fail, but contained no errors");
+      ASSERT.that(expected.getMessage()).contains("No files were generated.");
     }
   }
 
@@ -369,6 +386,37 @@ public SourceVersion getSupportedSourceVersion() {
     }
   }
 
+  private static final class FailingGeneratingProcessor extends AbstractProcessor {
+    static final String GENERATED_CLASS_NAME = GeneratingProcessor.GENERATED_CLASS_NAME;
+    static final String GENERATED_SOURCE = GeneratingProcessor.GENERATED_SOURCE;
+    static final String ERROR_MESSAGE = "expected error!";
+    final GeneratingProcessor delegate = new GeneratingProcessor();
+    Messager messager;
+
+    @Override
+    public synchronized void init(ProcessingEnvironment processingEnv) {
+      delegate.init(processingEnv);
+      this.messager = processingEnv.getMessager();
+    }
+
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+      delegate.process(annotations, roundEnv);
+      messager.printMessage(Kind.ERROR, ERROR_MESSAGE);
+      return false;
+    }
+
+    @Override
+    public Set<String> getSupportedAnnotationTypes() {
+      return delegate.getSupportedAnnotationTypes();
+    }
+
+    @Override
+    public SourceVersion getSupportedSourceVersion() {
+      return delegate.getSupportedSourceVersion();
+    }
+  }
+
   private static final class NoOpProcessor extends AbstractProcessor {
     boolean invoked = false;
 
