Add the 'googlemock' component of Google Test to LLVM's unittest libraries.
I have two immediate motivations for adding this:
1) It makes writing expectations in tests *dramatically* easier. A
quick example that is a taste of what is possible:
std::vector<int> v = ...;
EXPECT_THAT(v, UnorderedElementsAre(1, 2, 3));
This checks that v contains '1', '2', and '3' in some order. There
are a wealth of other helpful matchers like this. They tend to be
highly generic and STL-friendly so they will in almost all cases work
out of the box even on custom LLVM data structures.
I actually find the matcher syntax substantially easier to read even
for simple assertions:
EXPECT_THAT(a, Eq(b));
EXPECT_THAT(b, Ne(c));
Both of these make it clear what is being *tested* and what is being
*expected*. With `EXPECT_EQ` this is implicit (the LHS is expected,
the RHS is tested) and often confusing. With `EXPECT_NE` it is just
not clear. Even the failure error messages are superior with the
matcher based expectations.
2) When testing any kind of generic code, you are continually defining
dummy types with interfaces and then trying to check that the
interfaces are manipulated in a particular way. This is actually what
mocks are *good* for -- testing *interface interactions*. With
generic code, there is often no "fake" or other object that can be
used.
For a concrete example of where this is currently causing significant
pain, look at the pass manager unittests which are riddled with
counters incremented when methods are called. All of these could be
replaced with mocks. The result would be more effective at testing
the code by having tighter constraints. It would be substantially
more readable and maintainable when updating the code. And the error
messages on failure would have substantially more information as
mocks automatically record stack traces and other information *when
the API is misused* instead of trying to diagnose it after the fact.
I expect that #1 will be the overwhelming majority of the uses of gmock,
but I think that is sufficient to justify having it. I would actually
like to update the coding standards to encourage the use of matchers
rather than any other form of `EXPECT_...` macros as they are IMO
a strict superset in terms of functionality and readability.
I think that #2 is relatively rarely useful, but there *are* cases where
it is useful. Historically, I think misuse of actual mocking as
described in #2 has led to resistance towards this framework. I am
actually sympathetic to this -- mocking can easily be overused. However
I think this is not a significant concern in LLVM. First and foremost,
LLVM has very careful and rare exposure of abstract interfaces or
dependency injection, which are the most prone to abuse with mocks. So
there are few opportunities to abuse them. Second, a large fraction of
LLVM's unittests are testing *generic code* where mocks actually make
tremendous sense. And gmock is well suited to building interfaces that
exercise generic libraries. Finally, I still think we should be willing
to have testing utilities in tree even if they should be used rarely. We
can use code review to help guide the usage here.
For a longer and more complete discussion of this, see the llvm-dev
thread here:
http://lists.llvm.org/pipermail/llvm-dev/2017-January/108672.html
The general consensus seems that this is a reasonable direction to start
down, but that doesn't mean we should race ahead and use this
everywhere. I have one test that is blocked on this to land and that was
specifically used as an example. Before widespread adoption, I'm going
to work up some (brief) guidelines as some of these facilities should be
used sparingly and carefully.
Differential Revision: https://reviews.llvm.org/D28156
llvm-svn: 291606
diff --git a/llvm/utils/unittest/googlemock/src/gmock-internal-utils.cc b/llvm/utils/unittest/googlemock/src/gmock-internal-utils.cc
new file mode 100644
index 0000000..fb53080
--- /dev/null
+++ b/llvm/utils/unittest/googlemock/src/gmock-internal-utils.cc
@@ -0,0 +1,174 @@
+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: wan@google.com (Zhanyong Wan)
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file defines some utilities useful for implementing Google
+// Mock. They are subject to change without notice, so please DO NOT
+// USE THEM IN USER CODE.
+
+#include "gmock/internal/gmock-internal-utils.h"
+
+#include <ctype.h>
+#include <ostream> // NOLINT
+#include <string>
+#include "gmock/gmock.h"
+#include "gmock/internal/gmock-port.h"
+#include "gtest/gtest.h"
+
+namespace testing {
+namespace internal {
+
+// Converts an identifier name to a space-separated list of lower-case
+// words. Each maximum substring of the form [A-Za-z][a-z]*|\d+ is
+// treated as one word. For example, both "FooBar123" and
+// "foo_bar_123" are converted to "foo bar 123".
+GTEST_API_ string ConvertIdentifierNameToWords(const char* id_name) {
+ string result;
+ char prev_char = '\0';
+ for (const char* p = id_name; *p != '\0'; prev_char = *(p++)) {
+ // We don't care about the current locale as the input is
+ // guaranteed to be a valid C++ identifier name.
+ const bool starts_new_word = IsUpper(*p) ||
+ (!IsAlpha(prev_char) && IsLower(*p)) ||
+ (!IsDigit(prev_char) && IsDigit(*p));
+
+ if (IsAlNum(*p)) {
+ if (starts_new_word && result != "")
+ result += ' ';
+ result += ToLower(*p);
+ }
+ }
+ return result;
+}
+
+// This class reports Google Mock failures as Google Test failures. A
+// user can define another class in a similar fashion if he intends to
+// use Google Mock with a testing framework other than Google Test.
+class GoogleTestFailureReporter : public FailureReporterInterface {
+ public:
+ virtual void ReportFailure(FailureType type, const char* file, int line,
+ const string& message) {
+ AssertHelper(type == kFatal ?
+ TestPartResult::kFatalFailure :
+ TestPartResult::kNonFatalFailure,
+ file,
+ line,
+ message.c_str()) = Message();
+ if (type == kFatal) {
+ posix::Abort();
+ }
+ }
+};
+
+// Returns the global failure reporter. Will create a
+// GoogleTestFailureReporter and return it the first time called.
+GTEST_API_ FailureReporterInterface* GetFailureReporter() {
+ // Points to the global failure reporter used by Google Mock. gcc
+ // guarantees that the following use of failure_reporter is
+ // thread-safe. We may need to add additional synchronization to
+ // protect failure_reporter if we port Google Mock to other
+ // compilers.
+ static FailureReporterInterface* const failure_reporter =
+ new GoogleTestFailureReporter();
+ return failure_reporter;
+}
+
+// Protects global resources (stdout in particular) used by Log().
+static GTEST_DEFINE_STATIC_MUTEX_(g_log_mutex);
+
+// Returns true iff a log with the given severity is visible according
+// to the --gmock_verbose flag.
+GTEST_API_ bool LogIsVisible(LogSeverity severity) {
+ if (GMOCK_FLAG(verbose) == kInfoVerbosity) {
+ // Always show the log if --gmock_verbose=info.
+ return true;
+ } else if (GMOCK_FLAG(verbose) == kErrorVerbosity) {
+ // Always hide it if --gmock_verbose=error.
+ return false;
+ } else {
+ // If --gmock_verbose is neither "info" nor "error", we treat it
+ // as "warning" (its default value).
+ return severity == kWarning;
+ }
+}
+
+// Prints the given message to stdout iff 'severity' >= the level
+// specified by the --gmock_verbose flag. If stack_frames_to_skip >=
+// 0, also prints the stack trace excluding the top
+// stack_frames_to_skip frames. In opt mode, any positive
+// stack_frames_to_skip is treated as 0, since we don't know which
+// function calls will be inlined by the compiler and need to be
+// conservative.
+GTEST_API_ void Log(LogSeverity severity,
+ const string& message,
+ int stack_frames_to_skip) {
+ if (!LogIsVisible(severity))
+ return;
+
+ // Ensures that logs from different threads don't interleave.
+ MutexLock l(&g_log_mutex);
+
+ // "using ::std::cout;" doesn't work with Symbian's STLport, where cout is a
+ // macro.
+
+ if (severity == kWarning) {
+ // Prints a GMOCK WARNING marker to make the warnings easily searchable.
+ std::cout << "\nGMOCK WARNING:";
+ }
+ // Pre-pends a new-line to message if it doesn't start with one.
+ if (message.empty() || message[0] != '\n') {
+ std::cout << "\n";
+ }
+ std::cout << message;
+ if (stack_frames_to_skip >= 0) {
+#ifdef NDEBUG
+ // In opt mode, we have to be conservative and skip no stack frame.
+ const int actual_to_skip = 0;
+#else
+ // In dbg mode, we can do what the caller tell us to do (plus one
+ // for skipping this function's stack frame).
+ const int actual_to_skip = stack_frames_to_skip + 1;
+#endif // NDEBUG
+
+ // Appends a new-line to message if it doesn't end with one.
+ if (!message.empty() && *message.rbegin() != '\n') {
+ std::cout << "\n";
+ }
+ std::cout << "Stack trace:\n"
+ << ::testing::internal::GetCurrentOsStackTraceExceptTop(
+ ::testing::UnitTest::GetInstance(), actual_to_skip);
+ }
+ std::cout << ::std::flush;
+}
+
+} // namespace internal
+} // namespace testing