feat: make system tests skipable via env

cmake/Boost_DD.cmake

@@ -6,7 +6,7 @@ include_guard(GLOBAL)
 
 find_package(Boost 1.85)
 if(NOT Boost_FOUND)
-    message(STATUS "Boost v1.85.x package not found in system. Falling back to Fetch.")
+    message(STATUS "Boost v1.85.x package not found in the system. Falling back to FetchContent.")
     include(FetchContent)
 
     # Avoid warning about DOWNLOAD_EXTRACT_TIMESTAMP in CMake 3.24:

tests/fixtures/fixtures.cpp

@@ -11,6 +11,11 @@ BaseTest::BaseTest():
 
 void
 BaseTest::SetUp() {
+  if (const auto skip_reason { skipTest() }; !skip_reason.empty()) {
+    m_test_skipped_at_setup = true;
+    GTEST_SKIP() << skip_reason;
+  }
+
   // todo: only run this one time, instead of every time a test is run
   // see: https://stackoverflow.com/questions/2435277/googletest-accessing-the-environment-from-a-test
   // get command line args from the test executable
@@ -38,6 +43,13 @@ BaseTest::SetUp() {
 
 void
 BaseTest::TearDown() {
+  if (m_test_skipped_at_setup) {
+    // We are not using the IsSkipped() state here. Here we are skipping
+    // teardown, because we have skipped the setup entirely, but during normal
+    // skips we still want to do teardown.
+    return;
+  }
+
   display_device::Logger::get().setCustomCallback(nullptr);  // restore the default callback to avoid potential leaks
   std::cout.rdbuf(m_sbuf);  // restore cout buffer
 
@@ -67,6 +79,28 @@ BaseTest::TearDown() {
   }
 }
 
+bool
+BaseTest::isSystemTest() const {
+  return false;
+}
+
+std::string
+BaseTest::skipTest() const {
+  if (isSystemTest()) {
+    const static bool is_system_test_skippable {
+      []() {
+        const auto value { getEnv("SKIP_SYSTEM_TESTS") };
+        return value == "1";
+      }()
+    };
+
+    if (is_system_test_skippable) {
+      return "Skipping, this system test is disabled via SKIP_SYSTEM_TESTS=1 env.";
+    }
+  }
+  return {};
+}
+
 int
 BaseTest::exec(const char *cmd) {
   std::array<char, 128> buffer {};
@@ -81,62 +115,38 @@ BaseTest::exec(const char *cmd) {
   while (fgets(buffer.data(), buffer.size(), m_pipe_stderr) != nullptr) {
     m_stderr_buffer << buffer.data();
   }
-  int returnCode = pclose(m_pipe_stdout);
+  int return_code = pclose(m_pipe_stdout);
   m_pipe_stdout = nullptr;
-  if (returnCode != 0) {
+  if (return_code != 0) {
     std::cout << "Error: " << m_stderr_buffer.str() << std::endl
-              << "Return code: " << returnCode << std::endl;
+              << "Return code: " << return_code << std::endl;
   }
-  return returnCode;
+  return return_code;
 }
 
-void
-LinuxTest::SetUp() {
+std::string
+LinuxTest::skipTest() const {
 #ifndef __linux__
-  GTEST_SKIP_("Skipping, this test is for Linux only.");
+  return "Skipping, this test is for Linux only.";
+#else
+  return BaseTest::skipTest();
 #endif
-  BaseTest::SetUp();
 }
 
-void
-LinuxTest::TearDown() {
-#ifndef __linux__
-  // This a noop case to skip the teardown
-  return;
-#endif
-  BaseTest::TearDown();
-}
-
-void
-MacOSTest::SetUp() {
-#if !defined(__APPLE__) || !defined(__MACH__)
-  GTEST_SKIP_("Skipping, this test is for macOS only.");
-#endif
-  BaseTest::SetUp();
-}
-
-void
-MacOSTest::TearDown() {
+std::string
+MacOSTest::skipTest() const {
 #if !defined(__APPLE__) || !defined(__MACH__)
-  // This a noop case to skip the teardown
-  return;
+  return "Skipping, this test is for macOS only.";
+#else
+  return BaseTest::skipTest();
 #endif
-  BaseTest::TearDown();
 }
 
-void
-WindowsTest::SetUp() {
-#ifndef _WIN32
-  GTEST_SKIP_("Skipping, this test is for Windows only.");
-#endif
-  BaseTest::SetUp();
-}
-
-void
-WindowsTest::TearDown() {
+std::string
+WindowsTest::skipTest() const {
 #ifndef _WIN32
-  // This a noop case to skip the teardown
-  return;
+  return "Skipping, this test is for Windows only.";
+#else
+  return BaseTest::skipTest();
 #endif
-  BaseTest::TearDown();
 }

tests/fixtures/fixtures.h

@@ -59,6 +59,21 @@ class BaseTest: public ::testing::Test {
   void
   TearDown() override;
 
+  /**
+   * @brief Check if the test interacts/modifies with the system settings.
+   * @returns True if it does, false otherwise.
+   * @note By setting SKIP_SYSTEM_TESTS=1 env, these tests will be skipped (useful during development).
+   */
+  [[nodiscard]] virtual bool
+  isSystemTest() const;
+
+  /**
+   * @brief Skip the test by specifying the reason.
+   * @returns A non-empty string (reason) if test needs to be skipped, empty string otherwise.
+   */
+  [[nodiscard]] virtual std::string
+  skipTest() const;
+
   int
   exec(const char *cmd);
 
@@ -72,31 +87,25 @@ class BaseTest: public ::testing::Test {
   std::streambuf *m_sbuf;
   FILE *m_pipe_stdout;
   FILE *m_pipe_stderr;
+
+private:
+  bool m_test_skipped_at_setup { false };
 };
 
 class LinuxTest: public BaseTest {
 protected:
-  void
-  SetUp() override;
-
-  void
-  TearDown() override;
+  [[nodiscard]] std::string
+  skipTest() const override;
 };
 
 class MacOSTest: public BaseTest {
 protected:
-  void
-  SetUp() override;
-
-  void
-  TearDown() override;
+  [[nodiscard]] std::string
+  skipTest() const override;
 };
 
 class WindowsTest: public BaseTest {
 protected:
-  void
-  SetUp() override;
-
-  void
-  TearDown() override;
+  [[nodiscard]] std::string
+  skipTest() const override;
 };

tests/fixtures/testutils.cpp

@@ -1,6 +1,9 @@
 // header include
 #include "testutils.h"
 
+// system includes
+#include <cstdlib>
+
 // system includes
 #include <iostream>
 #include <regex>
@@ -26,3 +29,11 @@ setEnv(const std::string &name, const std::string &value) {
   return setenv(name.c_str(), value.c_str(), 1);
 #endif
 }
+
+std::optional<std::string>
+getEnv(const std::string &name) {
+  if (const auto value { std::getenv(name.c_str()) }; value) {
+    return std::string { value };
+  }
+  return std::nullopt;
+}

tests/fixtures/testutils.h

@@ -1,20 +1,29 @@
 #pragma once
 
 // system includes
+#include <optional>
 #include <string>
 
 /**
  * @brief Test regular expression against string.
- * @return True if string matches the regex, false otherwise
+ * @return True if string matches the regex, false otherwise.
  */
 bool
 testRegex(const std::string &test_pattern, const std::string &regex_pattern);
 
 /**
  * @brief Set an environment variable.
- * @param name Name of the environment variable
- * @param value Value of the environment variable
- * @return 0 on success, non-zero error code on failure
+ * @param name Name of the environment variable.
+ * @param value Value of the environment variable.
+ * @return 0 on success, non-zero error code on failure.
  */
 int
 setEnv(const std::string &name, const std::string &value);
+
+/**
+ * @brief Get an environment variable.
+ * @param name Name of the environment variable.
+ * @return String value of the variable or an empty optional otherwise.
+ */
+std::optional<std::string>
+getEnv(const std::string &name);

tests/unit/windows/test_windisplaydevicetopology.cpp

@@ -17,6 +17,11 @@ namespace {
   // Test fixture(s) for this file
   class WinDisplayDeviceTopology: public BaseTest {
   public:
+    bool
+    isSystemTest() const override {
+      return true;
+    }
+
     std::optional<std::vector<std::string>>
     getAvailableDevices() {
       const auto all_devices { m_layer->queryDisplayConfig(display_device::QueryType::All) };