Implements support for AssertionResult in Boolean assertions such as EXPECT_TRUE; Fixes Google Tests's tuple implementation to default-initialize its fields in the default constructor (by Zhanyong Wan); Populates gtest_stress_test.cc with actual tests.

git-svn-id: http://googletest.googlecode.com/svn/trunk@331 861a406c-534a-0410-8894-cb66d6ee9925

1 files changed, 115 insertions, 31 deletions

diff --git a/include/gtest/gtest.h b/include/gtest/gtest.h
index 9be15fb..33e2f7f 100644
--- a/include/gtest/gtest.h
+++ b/include/gtest/gtest.h
@@ -177,63 +177,145 @@ String StreamableToString(const T& streamable) {
 
 // A class for indicating whether an assertion was successful.  When
 // the assertion wasn't successful, the AssertionResult object
-// remembers a non-empty message that described how it failed.
+// remembers a non-empty message that describes how it failed.
 //
-// This class is useful for defining predicate-format functions to be
-// used with predicate assertions (ASSERT_PRED_FORMAT*, etc).
-//
-// The constructor of AssertionResult is private.  To create an
-// instance of this class, use one of the factory functions
+// To create an instance of this class, use one of the factory functions
 // (AssertionSuccess() and AssertionFailure()).
 //
-// For example, in order to be able to write:
+// This class is useful for two purposes:
+//   1. Defining predicate functions to be used with Boolean test assertions
+//      EXPECT_TRUE/EXPECT_FALSE and their ASSERT_ counterparts
+//   2. Defining predicate-format functions to be
+//      used with predicate assertions (ASSERT_PRED_FORMAT*, etc).
+//
+// For example, if you define IsEven predicate:
+//
+//   testing::AssertionResult IsEven(int n) {
+//     if ((n % 2) == 0)
+//       return testing::AssertionSuccess();
+//     else
+//       return testing::AssertionFailure() << n << " is odd";
+//   }
+//
+// Then the failed expectation EXPECT_TRUE(IsEven(Fib(5)))
+// will print the message
+//
+//   Value of: IsEven(Fib(5))
+//     Actual: false (5 is odd)
+//   Expected: true
+//
+// instead of a more opaque
+//
+//   Value of: IsEven(Fib(5))
+//     Actual: false
+//   Expected: true
+//
+// in case IsEven is a simple Boolean predicate.
+//
+// If you expect your predicate to be reused and want to support informative
+// messages in EXPECT_FALSE and ASSERT_FALSE (negative assertions show up
+// about half as often as positive ones in our tests), supply messages for
+// both success and failure cases:
+//
+//   testing::AssertionResult IsEven(int n) {
+//     if ((n % 2) == 0)
+//       return testing::AssertionSuccess() << n << " is even";
+//     else
+//       return testing::AssertionFailure() << n << " is odd";
+//   }
+//
+// Then a statement EXPECT_FALSE(IsEven(Fib(6))) will print
+//
+//   Value of: IsEven(Fib(6))
+//     Actual: true (8 is even)
+//   Expected: false
+//
+// NB: Predicates that support negative Boolean assertions have reduced
+// performance in positive ones so be careful not to use them in tests
+// that have lots (tens of thousands) of positive Boolean assertions.
+//
+// To use this class with EXPECT_PRED_FORMAT assertions such as:
 //
 //   // Verifies that Foo() returns an even number.
 //   EXPECT_PRED_FORMAT1(IsEven, Foo());
 //
-// you just need to define:
+// you need to define:
 //
 //   testing::AssertionResult IsEven(const char* expr, int n) {
-//     if ((n % 2) == 0) return testing::AssertionSuccess();
-//
-//     Message msg;
-//     msg << "Expected: " << expr << " is even\n"
-//         << "  Actual: it's " << n;
-//     return testing::AssertionFailure(msg);
+//     if ((n % 2) == 0)
+//       return testing::AssertionSuccess();
+//     else
+//       return testing::AssertionFailure()
+//         << "Expected: " << expr << " is even\n  Actual: it's " << n;
 //   }
 //
 // If Foo() returns 5, you will see the following message:
 //
 //   Expected: Foo() is even
 //     Actual: it's 5
+//
 class AssertionResult {
  public:
-  // Declares factory functions for making successful and failed
-  // assertion results as friends.
-  friend AssertionResult AssertionSuccess();
-  friend AssertionResult AssertionFailure(const Message&);
+  // Copy constructor.
+  // Used in EXPECT_TRUE/FALSE(assertion_result).
+  AssertionResult(const AssertionResult& other);
+  // Used in the EXPECT_TRUE/FALSE(bool_expression).
+  explicit AssertionResult(bool success) : success_(success) {}
 
   // Returns true iff the assertion succeeded.
-  operator bool() const { return failure_message_.c_str() == NULL; }  // NOLINT
+  operator bool() const { return success_; }  // NOLINT
+
+  // Returns the assertion's negation. Used with EXPECT/ASSERT_FALSE.
+  AssertionResult operator!() const;
+
+  // Returns the text streamed into this AssertionResult. Test assertions
+  // use it when they fail (i.e., the predicate's outcome doesn't match the
+  // assertion's expectation). When nothing has been streamed into the
+  // object, returns an empty string.
+  const char* message() const {
+    return message_.get() != NULL && message_->c_str() != NULL ?
+           message_->c_str() : "";
+  }
+  // TODO(vladl@google.com): Remove this after making sure no clients use it.
+  // Deprecated; please use message() instead.
+  const char* failure_message() const { return message(); }
 
-  // Returns the assertion's failure message.
-  const char* failure_message() const { return failure_message_.c_str(); }
+  // Streams a custom failure message into this object.
+  template <typename T> AssertionResult& operator<<(const T& value);
 
  private:
-  // The default constructor.  It is used when the assertion succeeded.
-  AssertionResult() {}
-
-  // The constructor used when the assertion failed.
-  explicit AssertionResult(const internal::String& failure_message);
-
-  // Stores the assertion's failure message.
-  internal::String failure_message_;
-};
+  // No implementation - we want AssertionResult to be
+  // copy-constructible but not assignable.
+  void operator=(const AssertionResult& other);
+
+  // Stores result of the assertion predicate.
+  bool success_;
+  // Stores the message describing the condition in case the expectation
+  // construct is not satisfied with the predicate's outcome.
+  // Referenced via a pointer to avoid taking too much stack frame space
+  // with test assertions.
+  internal::scoped_ptr<internal::String> message_;
+};  // class AssertionResult
+
+// Streams a custom failure message into this object.
+template <typename T>
+AssertionResult& AssertionResult::operator<<(const T& value) {
+  Message msg;
+  if (message_.get() != NULL)
+    msg << *message_;
+  msg << value;
+  message_.reset(new internal::String(msg.GetString()));
+  return *this;
+}
 
 // Makes a successful assertion result.
 AssertionResult AssertionSuccess();
 
+// Makes a failed assertion result.
+AssertionResult AssertionFailure();
+
 // Makes a failed assertion result with the given failure message.
+// Deprecated; use AssertionFailure() << msg.
 AssertionResult AssertionFailure(const Message& msg);
 
 // The abstract class that all tests inherit from.
@@ -1603,7 +1685,9 @@ const T* TestWithParam<T>::parameter_ = NULL;
 #define ASSERT_ANY_THROW(statement) \
   GTEST_TEST_ANY_THROW_(statement, GTEST_FATAL_FAILURE_)
 
-// Boolean assertions.
+// Boolean assertions. Condition can be either a Boolean expression or an
+// AssertionResult. For more information on how to use AssertionResult with
+// these macros see comments on that class.
 #define EXPECT_TRUE(condition) \
   GTEST_TEST_BOOLEAN_(condition, #condition, false, true, \
                       GTEST_NONFATAL_FAILURE_)