unittests: add ErrorStr to ExecutionEngine test

Makes failures more self-explanatory.

llvm-svn: 145704

Author: nobled

llvm/unittests/ExecutionEngine/ExecutionEngineTest.cpp

@@ -22,12 +22,13 @@ namespace {
 class ExecutionEngineTest : public testing::Test {
 protected:
   ExecutionEngineTest()
-    : M(new Module("<main>", getGlobalContext())),
-      Engine(EngineBuilder(M).create()) {
+    : M(new Module("<main>", getGlobalContext())), Error(""),
+      Engine(EngineBuilder(M).setErrorStr(&Error).create()) {
   }
 
   virtual void SetUp() {
-    ASSERT_TRUE(Engine.get() != NULL);
+    ASSERT_TRUE(Engine.get() != NULL) << "EngineBuilder returned error: '"
+      << Error << "'";
   }
 
   GlobalVariable *NewExtGlobal(Type *T, const Twine &Name) {
@@ -36,6 +37,7 @@ class ExecutionEngineTest : public testing::Test {
   }
 
   Module *const M;
+  std::string Error;
   const OwningPtr<ExecutionEngine> Engine;
 };