Add a context stack to Reporter, for better error messages

Currently, just inject the Ganesh context type when running unit tests.
Obviously, we can use this to supply other contextual information around
tests that do many variations of configs, formats, etc...

BUG=skia:

Change-Id: Iab96632a92ec632e4d132bbcc17a91a8dd251e78
Reviewed-on: https://skia-review.googlesource.com/5565
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 38 insertions, 1 deletions

diff --git a/tests/Test.h b/tests/Test.h
index ea10cdf7e3..8b60039da0 100644
--- a/tests/Test.h
+++ b/tests/Test.h
@@ -44,10 +44,47 @@ public:
     virtual bool allowExtendedTest() const;
     virtual bool verbose() const;
     virtual void* stats() const { return nullptr; }
+
+    void reportFailedWithContext(const skiatest::Failure& f) {
+        SkString fullMessage = f.message;
+        if (!fContextStack.empty()) {
+            fullMessage.append(" [");
+            for (int i = 0; i < fContextStack.count(); ++i) {
+                if (i > 0) {
+                    fullMessage.append(", ");
+                }
+                fullMessage.append(fContextStack[i]);
+            }
+            fullMessage.append("]");
+        }
+        this->reportFailed(skiatest::Failure(f.fileName, f.lineNo, f.condition, fullMessage));
+    }
+    void push(const SkString& message) {
+        fContextStack.push_back(message);
+    }
+    void pop() {
+        fContextStack.pop_back();
+    }
+
+private:
+    SkTArray<SkString> fContextStack;
 };
 
 #define REPORT_FAILURE(reporter, cond, message) \
-    reporter->reportFailed(skiatest::Failure(__FILE__, __LINE__, cond, message))
+    reporter->reportFailedWithContext(skiatest::Failure(__FILE__, __LINE__, cond, message))
+
+class ReporterContext : SkNoncopyable {
+public:
+    ReporterContext(Reporter* reporter, const SkString& message) : fReporter(reporter) {
+        fReporter->push(message);
+    }
+    ~ReporterContext() {
+        fReporter->pop();
+    }
+
+private:
+    Reporter* fReporter;
+};
 
 typedef void (*TestProc)(skiatest::Reporter*, sk_gpu_test::GrContextFactory*);