add unittest for cmake preprocessing

it uses the existing 14 configure file test case to configure
config 7 and 10 with cmake and meson and then compares the
relevant output to see if they are equal

Author: Jan200101

test cases/common/14 configure file/CMakeLists.txt

@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 3.12)
+
+project("configure file test" LANGUAGES C)
+
+set("var1" "foo")
+set("var2" "bar")
+configure_file("config7.h.in" "config7.h")
+
+set("var" "foo")
+configure_file("config10.h.in" "config10.h")

unittests/allplatformstests.py

@@ -222,6 +222,47 @@ def check_formats(confdata, result):
         confdata.values = {'VAR': (['value'], 'description')}
         self.assertRaises(MesonException, conf_str, ['#mesondefine VAR'], confdata, 'meson')
 
+    def test_cmake_configuration(self):
+        if self.backend is not Backend.ninja:
+            raise SkipTest('ninja backend needed to configure with cmake')
+
+        cmake = ExternalProgram('cmake')
+        if not cmake.found():
+            raise SkipTest('cmake not available')
+
+        cmake_version = cmake.get_version()
+        if not version_compare(cmake_version, '>=3.13.5'):
+            raise SkipTest('cmake is too old')
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            srcdir = os.path.join(tmpdir, 'src')
+
+            shutil.copytree(os.path.join(self.src_root, 'test cases', 'common', '14 configure file'), srcdir)
+            self.init(srcdir)
+
+            cmake_builddir = os.path.join(srcdir, "cmake_builddir")
+            self.assertNotEqual(self.builddir, cmake_builddir)
+            self._run([cmake.path, '-G', 'Ninja', '-S', srcdir, '-B', cmake_builddir])
+
+            header_list = [
+                'config7.h',
+                'config10.h',
+            ]
+
+            for header in header_list:
+                meson_header = ""
+                cmake_header = ""
+
+                with open(os.path.join(self.builddir, header), encoding='utf-8') as f:
+                    meson_header = f.read()
+
+                cmake_header_path = os.path.join(cmake_builddir, header)
+                with open(os.path.join(cmake_builddir, header), encoding='utf-8') as f:
+                    cmake_header = f.read()
+
+                self.assertTrue(cmake_header, f'cmake generated header {header} is empty')
+                self.assertEqual(cmake_header, meson_header)
+
     def test_absolute_prefix_libdir(self):
         '''
         Tests that setting absolute paths for --prefix and --libdir work. Can't