Rework CI for C++2020 tests

azure-pipelines.yml

@@ -18,10 +18,12 @@ stages:
     parameters:
       jobName: 'Validate GCC latest'
       imageName: ubuntu-20.04
+      CXXVersions: [ 14, 17 ]
   - template: ./pipelines/jobs.yml
     parameters:
       jobName: 'Validate GCC Previous'
       imageName: ubuntu-18.04
+      CXXVersions: [ 14, 17 ]
 
 # Clang
 - stage: Clang
@@ -40,6 +42,7 @@ stages:
     parameters:
       jobName: 'Validate Clang Previous'
       imageName: ubuntu-18.04
+      CXXVersions: [ 14, 17 ]
 
 # MSVC
 - stage: MSVC
@@ -53,6 +56,7 @@ stages:
     parameters:
       jobName: 'Validate MSVC Previous'
       imageName: vs2017-win2016
+      CXXVersions: [ 14, 17 ]
 
 # Apple-Clang
 - stage: Apple_Clang
@@ -62,7 +66,9 @@ stages:
     parameters:
       jobName: 'Validate Apple-Clang latest'
       imageName: macos-10.15
+      CXXVersions: [ 14, 17 ]
   - template: ./pipelines/jobs.yml
     parameters:
       jobName: 'Validate Apple-Clang Previous'
       imageName: macos-10.14
+      CXXVersions: [ 14, 17 ]

pipelines/jobs.yml

@@ -1,33 +1,19 @@
 parameters:
   jobName: ''
   imageName: ''
+  CXXVersions: [ 14, 17, 20 ]
+  buildTypes: [ 'Debug', 'Release' ]
 
 jobs:
-- job:
-  displayName: ${{ parameters.imageName }}
-  pool:
-    vmImage: ${{ parameters.imageName }}
-  strategy:
-    matrix:
-      14_debug:
-        GSL_CXX_STANDARD: '14'
-        BUILD_TYPE: 'Debug'
-      14_release:
-        GSL_CXX_STANDARD: '14'
-        BUILD_TYPE: 'Release'
-      17_debug:
-        GSL_CXX_STANDARD: '17'
-        BUILD_TYPE: 'Debug'
-      17_release:
-        GSL_CXX_STANDARD: '17'
-        BUILD_TYPE: 'Release'
-      # Note: Currently, only some C++20 features are supported by GSL
-      20_debug:
-        GSL_CXX_STANDARD: '20'
-        BUILD_TYPE: 'Debug'
-      20_release:
-        GSL_CXX_STANDARD: '20'
-        BUILD_TYPE: 'Release'
-  continueOnError: false
-  steps:
-  - template: ./steps.yml
+- ${{ each CXXVersion in parameters.CXXVersions }}:
+  - ${{ each buildType in parameters.buildTypes }}:
+    - job:
+      displayName: ${{ format('{0} {1} C++{2}', parameters.imageName, buildType, CXXVersion) }}
+      pool:
+        vmImage: ${{ parameters.imageName }}
+      continueOnError: false
+      steps:
+      - template: ./steps.yml
+        parameters:
+          buildType: ${{ buildType }}
+          CXXVersion: ${{ CXXVersion }}

pipelines/steps.yml

@@ -1,9 +1,13 @@
+parameters:
+    buildType: ''
+    CXXVersion: ''
+
 steps:
   - task: CMake@1
     name: Configure
     inputs:
       workingDirectory: build
-      cmakeArgs: '-DGSL_CXX_STANDARD=$(GSL_CXX_STANDARD) -DCMAKE_BUILD_TYPE=$(BUILD_TYPE) -Werror=dev .. '
+      cmakeArgs: '-DGSL_CXX_STANDARD=${{ parameters.CXXVersion }} -DCMAKE_BUILD_TYPE=${{ parameters.buildType }} -DCI_TESTING:BOOL=ON -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON -Werror=dev .. '
 
   - task: CMake@1
     name: Build

tests/CMakeLists.txt

@@ -9,6 +9,10 @@ include(ExternalProject)
 # will make visual studio generated project group files
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
+if(CI_TESTING AND GSL_CXX_STANDARD EQUAL 20)
+    add_compile_definitions(FORCE_STD_SPAN_TESTS=1)
+endif()
+
 if(IOS)
     add_compile_definitions(GTEST_HAS_DEATH_TEST=1 IOS_PROCESS_DELAY_WORKAROUND=1)
 endif()

tests/at_tests.cpp

@@ -119,7 +119,7 @@ TEST(at_tests, InitializerList)
     EXPECT_DEATH(gsl::at({1, 2, 3, 4}, 4), expected);
 }
 
-#if defined(__cplusplus) && __cplusplus >= 202002L
+#if defined(FORCE_STD_SPAN_TESTS) || defined(__cpp_lib_span) && __cpp_lib_span >= 202002L
 TEST(at_tests, std_span)
 {
     std::vector<int> vec{1, 2, 3, 4, 5};
@@ -145,7 +145,7 @@ TEST(at_tests, std_span)
     EXPECT_DEATH(gsl::at(csp, -1), expected);
     EXPECT_DEATH(gsl::at(csp, gsl::narrow_cast<gsl::index>(sp.size())), expected);
 }
-#endif // __cplusplus >= 202002L
+#endif // defined(FORCE_STD_SPAN_TESTS) || defined(__cpp_lib_span) && __cpp_lib_span >= 202002L
 
 #if !defined(_MSC_VER) || defined(__clang__) || _MSC_VER >= 1910
 static constexpr bool test_constexpr()