Add dynamic test discovery for for Google Test

Add a new gtest_discover_tests function to GoogleTest.cmake,
implementing dynamic test discovery (i.e. tests are discovered by
actually running the test executable and asking for the list of
available tests, which is used to dynamically declare the tests) rather
than the source-parsing approach used by gtest_add_tests. Compared to
the source-parsing approach, this has the advantage of being robust
against users declaring tests in unusual ways, and much better support
for advanced features such as parameterized tests.

A unit test, modeled after the TEST_INCLUDE_DIR[S] test, is also
included. Note that the unit test does not actually require that Google
Test is available. The new functionality does not actually depend on
Google Test as such; it only requires that the test executable lists
tests in the expected format when invoked with --gtest_list_tests, which
the unit test can fake readily.

6 files changed, 111 insertions, 0 deletions

diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 347b9d2366..13df4a8902 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -148,6 +148,7 @@ add_RunCMake_test(GeneratorExpression)
 add_RunCMake_test(GeneratorPlatform)
 add_RunCMake_test(GeneratorToolset)
 add_RunCMake_test(GNUInstallDirs -DSYSTEM_NAME=${CMAKE_SYSTEM_NAME})
+add_RunCMake_test(GoogleTest) # Note: does not actually depend on Google Test
 add_RunCMake_test(TargetPropertyGeneratorExpressions)
 add_RunCMake_test(Languages)
 add_RunCMake_test(LinkStatic)
diff --git a/Tests/RunCMake/GoogleTest/CMakeLists.txt b/Tests/RunCMake/GoogleTest/CMakeLists.txt
new file mode 100644
index 0000000000..dc92486973
--- /dev/null
+++ b/Tests/RunCMake/GoogleTest/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.6)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/GoogleTest/GoogleTest-test-stdout.txt b/Tests/RunCMake/GoogleTest/GoogleTest-test-stdout.txt
new file mode 100644
index 0000000000..5f7753dba1
--- /dev/null
+++ b/Tests/RunCMake/GoogleTest/GoogleTest-test-stdout.txt
@@ -0,0 +1,25 @@
+Test project .*
+    Start 1: TEST:basic\.case_foo!1
+1/8 Test #1: TEST:basic\.case_foo!1 \.+ +Passed +[0-9.]+ sec
+    Start 2: TEST:basic\.case_bar!1
+2/8 Test #2: TEST:basic\.case_bar!1 \.+ +Passed +[0-9.]+ sec
+    Start 3: TEST:basic\.disabled_case!1
+3/8 Test #3: TEST:basic\.disabled_case!1 \.+\*+Not Run \(Disabled\) +[0-9.]+ sec
+    Start 4: TEST:disabled\.case!1
+4/8 Test #4: TEST:disabled\.case!1 \.+\*+Not Run \(Disabled\) +[0-9.]+ sec
+    Start 5: TEST:typed/short\.case!1
+5/8 Test #5: TEST:typed/short\.case!1 \.+ +Passed +[0-9.]+ sec
+    Start 6: TEST:typed/float\.case!1
+6/8 Test #6: TEST:typed/float\.case!1 \.+ +Passed +[0-9.]+ sec
+    Start 7: TEST:value/test\.case/1!1
+7/8 Test #7: TEST:value/test\.case/1!1 \.+ +Passed +[0-9.]+ sec
+    Start 8: TEST:value/test\.case/"foo"!1
+8/8 Test #8: TEST:value/test\.case/"foo"!1 \.+ +Passed +[0-9.]+ sec
+
+100% tests passed, 0 tests failed out of 6
+
+Total Test time \(real\) = +[0-9.]+ sec
+
+The following tests did not run:
+.*3 - TEST:basic\.disabled_case!1 \(Disabled\)
+.*4 - TEST:disabled\.case!1 \(Disabled\)
diff --git a/Tests/RunCMake/GoogleTest/GoogleTest.cmake b/Tests/RunCMake/GoogleTest/GoogleTest.cmake
new file mode 100644
index 0000000000..9a3677fae7
--- /dev/null
+++ b/Tests/RunCMake/GoogleTest/GoogleTest.cmake
@@ -0,0 +1,15 @@
+project(test_include_dirs)
+include(CTest)
+include(GoogleTest)
+
+enable_testing()
+
+add_executable(fake_gtest fake_gtest.cpp)
+
+gtest_discover_tests(
+  fake_gtest
+  TEST_PREFIX TEST:
+  TEST_SUFFIX !1
+  EXTRA_ARGS how now "\"brown\" cow"
+  PROPERTIES LABELS TEST
+)
diff --git a/Tests/RunCMake/GoogleTest/RunCMakeTest.cmake b/Tests/RunCMake/GoogleTest/RunCMakeTest.cmake
new file mode 100644
index 0000000000..aec8568d05
--- /dev/null
+++ b/Tests/RunCMake/GoogleTest/RunCMakeTest.cmake
@@ -0,0 +1,26 @@
+include(RunCMake)
+
+function(run_GoogleTest)
+  # Use a single build tree for a few tests without cleaning.
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/GoogleTest-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  if(RunCMake_GENERATOR MATCHES "Make|Ninja")
+    set(RunCMake_TEST_OPTIONS -DCMAKE_BUILD_TYPE=Debug)
+  endif()
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+  run_cmake(GoogleTest)
+  run_cmake_command(GoogleTest-build
+    ${CMAKE_COMMAND}
+    --build .
+    --config Debug
+  )
+  run_cmake_command(GoogleTest-test
+    ${CMAKE_CTEST_COMMAND}
+    -C Debug
+    -L TEST
+    --no-label-summary
+  )
+endfunction()
+
+run_GoogleTest()
diff --git a/Tests/RunCMake/GoogleTest/fake_gtest.cpp b/Tests/RunCMake/GoogleTest/fake_gtest.cpp
new file mode 100644
index 0000000000..f1bd7efc8d
--- /dev/null
+++ b/Tests/RunCMake/GoogleTest/fake_gtest.cpp
@@ -0,0 +1,41 @@
+#include <iostream>
+#include <string>
+
+int main(int argc, char** argv)
+{
+  // Note: GoogleTest.cmake doesn't actually depend on Google Test as such;
+  // it only requires that we produces output in the expected format when
+  // invoked with --gtest_list_tests. Thus, we fake that here. This allows us
+  // to test the module without actually needing Google Test.
+  if (argc > 1 && std::string(argv[1]) == "--gtest_list_tests") {
+    std::cout << "basic." << std::endl;
+    std::cout << "  case_foo" << std::endl;
+    std::cout << "  case_bar" << std::endl;
+    std::cout << "  DISABLED_disabled_case" << std::endl;
+    std::cout << "DISABLED_disabled." << std::endl;
+    std::cout << "  case" << std::endl;
+    std::cout << "typed/0.  # TypeParam = short" << std::endl;
+    std::cout << "  case" << std::endl;
+    std::cout << "typed/1.  # TypeParam = float" << std::endl;
+    std::cout << "  case" << std::endl;
+    std::cout << "value/test." << std::endl;
+    std::cout << "  case/0  # GetParam() = 1" << std::endl;
+    std::cout << "  case/1  # GetParam() = \"foo\"" << std::endl;
+    return 0;
+  }
+
+  if (argc > 5) {
+    // Simple test of EXTRA_ARGS
+    if (std::string(argv[3]) == "how" && std::string(argv[4]) == "now" &&
+        std::string(argv[5]) == "\"brown\" cow") {
+      return 0;
+    }
+  }
+
+  // Print arguments for debugging, if we didn't get the expected arguments
+  for (int i = 1; i < argc; ++i) {
+    std::cerr << "arg[" << i << "]: '" << argv[i] << "'\n";
+  }
+
+  return 1;
+}