[CDRIVER-6107] Add Test Case Tag Support (#2135)

* `mlib_check` supports an explanatory string with all assertions
* Define a mutable string type
* Add a "vector" template header
* String functions for trimming whitespace
* Use mlib strings and vec types in TestSuite files
* Add support for test cases to declare tags (labels)

This change allows for test cases to declare any number of associated
"tags". The tags are specified after the test case name string as a
list of bracketed tags, mimicking Catch2's syntax.

The LoadTests.cmake script has been modified to apply test case's declared
tags as CTest labels. This also gives us the ability to apply test
fixture requirements granularly on only tests that declare their
requirement (via a tag).

* Tests can declare resource locks in tags
* No -Wmissing-braces anywhere
* Define a CTest fixture for our simple HTTP server
* Add test tags and properties throughout
* Fix OpenSSL test that requires an SSL context
* Add "unlikely" annotations around direct overflow checks

Author: vector-of-bool

.clang-format

@@ -149,6 +149,7 @@ ForEachMacros:
   - mlib_foreach_urange
   - mlib_foreach
   - mlib_foreach_arr
+  - mlib_vec_foreach
 IfMacros:
   - mlib_assert_aborts
   - KJ_IF_MAYBE

CMakeLists.txt

@@ -292,6 +292,7 @@ if(ENABLE_MAINTAINER_FLAGS)
       gnu-like:-Wuninitialized
       # Disabled, for now:
       gnu-like:-Wno-strict-aliasing
+      gnu-like:-Wno-missing-braces
       # Sign-comparison-mismatch:
       gnu-like:-Wsign-compare
       msvc:/we4018

Earthfile

@@ -137,6 +137,7 @@ PREP_CMAKE:
     FUNCTION
     # Run all CMake commands using uvx:
     RUN __alias cmake uvx cmake
+    RUN __alias ctest uvx --from=cmake ctest
     # Executing any CMake command will warm the cache:
     RUN cmake --version | head -n 1
 

build/cmake/LoadTests.cmake

@@ -3,57 +3,88 @@
 # allowing CTest to control the execution, parallelization, and collection of
 # test results.
 
-if (NOT EXISTS "${TEST_LIBMONGOC_EXE}")
+if(NOT EXISTS "${TEST_LIBMONGOC_EXE}")
     # This will fail if 'test-libmongoc' is not compiled yet.
-    message (WARNING "The test executable ${TEST_LIBMONGOC_EXE} is not present. "
-                     "Its tests will not be registered")
-    add_test (mongoc/not-found NOT_FOUND)
-    return ()
-endif ()
-
-# Get the list of tests
-execute_process (
-    COMMAND "${TEST_LIBMONGOC_EXE}" --list-tests --no-fork
-    OUTPUT_VARIABLE tests_out
+    message(WARNING "The test executable ${TEST_LIBMONGOC_EXE} is not present. "
+                    "Its tests will not be registered")
+    add_test(mongoc/not-found NOT_FOUND)
+    return()
+endif()
+
+# Get the list of tests. This command emits CMake code that defines variables for
+# all test cases defined in the suite
+execute_process(
+    COMMAND "${TEST_LIBMONGOC_EXE}" --tests-cmake --no-fork
+    OUTPUT_VARIABLE tests_cmake
     WORKING_DIRECTORY "${SRC_ROOT}"
     RESULT_VARIABLE retc
     )
-if (retc)
+if(retc)
     # Failed to list the tests. That's bad.
-    message (FATAL_ERROR "Failed to run test-libmongoc to discover tests [${retc}]:\n${tests_out}")
-endif ()
+    message(FATAL_ERROR "Failed to run test-libmongoc to discover tests [${retc}]:\n${tests_out}")
+endif()
 
-# Split lines on newlines
-string (REPLACE "\n" ";" lines "${tests_out}")
+# Execute the code that defines the test case information
+cmake_language(EVAL CODE "${tests_cmake}")
 
-# TODO: Allow individual test cases to specify the fixtures they want.
-set (all_fixtures "mongoc/fixtures/fake_kms_provider_server")
-set (all_env
+# Define environment variables that are common to all test cases
+set(all_env
     TEST_KMS_PROVIDER_HOST=localhost:14987  # Refer: Fixtures.cmake
     )
 
-# Generate the test definitions
-foreach (line IN LISTS lines)
-    if (NOT line MATCHES "^/")
-        # Only generate if the line begins with `/`, which all tests should.
-        continue ()
-    endif ()
-    # The new test name is prefixed with 'mongoc'
-    set (test "mongoc${line}")
-    # Define the test. Use `--ctest-run` to tell it that CTest is in control.
-    add_test ("${test}" "${TEST_LIBMONGOC_EXE}" --ctest-run "${line}")
-    set_tests_properties ("${test}" PROPERTIES
+function(list_select list_var)
+    cmake_parse_arguments(PARSE_ARGV 1 arg "" "SELECT;REPLACE;OUT" "")
+    set(seq "${${list_var}}")
+    list(FILTER seq INCLUDE REGEX "${arg_SELECT}")
+    list(TRANSFORM seq REPLACE "${arg_SELECT}" "${arg_REPLACE}")
+    set("${arg_OUT}" "${seq}" PARENT_SCOPE)
+endfunction()
+
+# The emitted code defines a list MONGOC_TESTS with the name of every test case
+# in the suite.
+foreach(casename IN LISTS MONGOC_TESTS)
+    set(name "mongoc${casename}")
+    # Run the program with --ctest-run to select only this one test case
+    add_test("${name}" "${TEST_LIBMONGOC_EXE}" --ctest-run "${casename}")
+    # The emitted code defines a TAGS list for every test case that it emits. We use
+    # these as the LABELS for the test case
+    unset(labels)
+    set(labels "${MONGOC_TEST_${casename}_TAGS}")
+
+    # Find what test fixtures the test wants by inspecting labels. Each "uses:"
+    # label defines the names of the test fixtures that a particular case requires
+    list_select(labels SELECT "^uses:(.*)$" REPLACE "mongoc/fixtures/\\1" OUT fixtures)
+
+    # For any "lock:..." labels, add a resource lock with the corresponding name
+    list_select(labels SELECT "^lock:(.*)$" REPLACE "\\1" OUT locks)
+
+    # Tests can set a timeout with a tag:
+    list_select(labels SELECT "^timeout:(.*)$" REPLACE "\\1" OUT timeout)
+    if(NOT timeout)
+        # Default timeout of 10 seconds. If a test takes longer than this, it either
+        # has a bug or it needs to declare a longer timeout.
+        set(timeout 10)
+    endif()
+
+    # Add a label for all test cases generated via this script so that they
+    # can be (de)selected separately:
+    list(APPEND labels test-libmongoc-generated)
+    # Set up the test:
+    set_tests_properties("${name}" PROPERTIES
         # test-libmongoc expects to execute in the root of the source directory
         WORKING_DIRECTORY "${SRC_ROOT}"
         # If a test emits '@@ctest-skipped@@', this tells us that the test is
         # skipped.
         SKIP_REGULAR_EXPRESSION "@@ctest-skipped@@"
-        # 45 seconds of timeout on each test.
-        TIMEOUT 45
-        FIXTURES_REQUIRED "${all_fixtures}"
+        # Apply a timeout to each test, either the default or one from test tags
+        TIMEOUT "${timeout}"
+        # Common environment variables:
         ENVIRONMENT "${all_env}"
-        # Mark all tests generated from the executable, so they can be (de)selected
-        # for execution separately.
-        LABELS "test-libmongoc-generated"
-        )
-endforeach ()
+        # Apply the labels
+        LABELS "${labels}"
+        # Fixture requirements:
+        FIXTURES_REQUIRED "${fixtures}"
+        # Test may lock resources:
+        RESOURCE_LOCK "${locks}"
+    )
+endforeach()

build/cmake/MongoC-Warnings.cmake

@@ -103,4 +103,4 @@ mongoc_add_warning_options (
 
      # Aside: Disable CRT insecurity warnings
      msvc:/D_CRT_SECURE_NO_WARNINGS
-     )
+)

build/cmake/TestFixtures.cmake

@@ -47,3 +47,11 @@ mongo_define_subprocess_fixture(
         "${_MONGOC_BUILD_SCRIPT_DIR}/bottle.py" fake_kms_provider_server:kms_provider
             --bind localhost:14987  # Port 14987 chosen arbitrarily
     )
+
+# Run our very simple HTTP server in a fixture process
+mongo_define_subprocess_fixture(
+    mongoc/fixtures/simple-http-server-18000
+    SPAWN_WAIT 1
+    COMMAND
+        $<TARGET_FILE:Python3::Interpreter> -u "${mongo-c-driver_SOURCE_DIR}/.evergreen/scripts/simple_http_server.py"
+    )

src/common/src/mlib/config.h

@@ -397,4 +397,23 @@
    MLIB_IF_GNU_LIKE(mlib_gnu_warning_disable("-Wunused-parameter");) \
    MLIB_IF_MSVC(mlib_msvc_warning(disable : 4100);) mlib_static_assert(1, "")
 
+#if mlib_is_clang()
+#define mlib_printf_attribute(f, v) __attribute__((format(printf, f, v)))
+#elif mlib_is_gcc()
+#define mlib_printf_attribute(f, v) __attribute__((format(gnu_printf, f, v)))
+#else
+#define mlib_printf_attribute(f, v)
+#endif
+
+/**
+ * @brief Annotate a boolean expression as "likely to be true" to guide the optimizer.
+ * Use this very sparingly.
+ */
+#define mlib_likely(...) MLIB_IF_ELSE(mlib_is_gnu_like())(__builtin_expect(!!(__VA_ARGS__), 1))((__VA_ARGS__))
+/**
+ * @brief Annotate a boolean expression as "likely to be untrue" to guide the optimizer.
+ * Use this very sparingly.
+ */
+#define mlib_unlikely(...) MLIB_IF_ELSE(mlib_is_gnu_like())(__builtin_expect(!!(__VA_ARGS__), 0))((__VA_ARGS__))
+
 #endif // MLIB_CONFIG_H_INCLUDED