Make the 'framework/4 qt' test more flexible

Make the 'framework/4 qt' test more flexible about what version of Qt is
expected to be present in the CI environment. Currently, this is
hard-coded as Qt5. We add an option to specify it so we can run this
test under CI with just Qt4 present.

.github/workflows/ci_frameworks.yml

@@ -71,7 +71,7 @@ jobs:
     - run: brew install pkg-config ninja gcc
     - run: brew tap cartr/qt4
     - run: brew install qt@4
-    - run: meson setup "test cases/frameworks/4 qt" build
+    - run: meson setup "test cases/frameworks/4 qt" build -Drequired=qt4
     - run: ninja -C build
     - uses: actions/upload-artifact@v1
       if: failure()

test cases/frameworks/4 qt/meson.build

@@ -21,19 +21,25 @@ foreach qt : ['qt4', 'qt5']
     error('Invalid qt dep incorrectly found!')
   endif
 
-  # This test should be skipped if qt5 isn't found
-  if qt == 'qt5'
+  # This test should be skipped if the required version of Qt isn't found
+  #
+  # (In the CI environment, the specified version of Qt is definitely present.
+  # An unexpected skip here is treated as a failure, so we are testing that the
+  # detection mechanism is able to find Qt.)
+  needed_qt = get_option('required').to_lower()
+  required = (qt == needed_qt)
+  if required
     dep = dependency(qt, modules : ['Core'], required : false, method : get_option('method'))
     if not dep.found()
-      error('MESON_SKIP_TEST qt5 not found.')
+      error('MESON_SKIP_TEST @0@ not found.'.format(needed_qt))
     endif
   endif
 
   # Ensure that the "no-Core-module-specified" code branch is hit
-  nocoredep = dependency(qt, modules : ['Gui'], required : qt == 'qt5', method : get_option('method'))
+  nocoredep = dependency(qt, modules : ['Gui'], required : required, method : get_option('method'))
 
-  # If qt4 modules are found, test that. qt5 is required.
-  qtdep = dependency(qt, modules : qt_modules, main : true, private_headers: true, required : qt == 'qt5', method : get_option('method'))
+  # If 'qt' modules are found, test that.
+  qtdep = dependency(qt, modules : qt_modules, main : true, private_headers: true, required : required, method : get_option('method'))
   if qtdep.found()
     qtmodule = import(qt)
 

test cases/frameworks/4 qt/meson_options.txt

@@ -1 +1,2 @@
 option('method', type : 'string', value : 'auto', description : 'The method to use to find Qt')
+option('required', type : 'string', value : 'qt5', description : 'The version of Qt which is required to be present')