Use a mocked pkg-config in test

Signed-off-by: Mats Wichmann <mats@linux.com>

Author: mwichmann

test/CPPDEFINES/pkg-config.py

@@ -26,70 +26,42 @@
 """
 Verify merging with MergeFlags to CPPPDEFINES with various data types.
 
-Uses system pkg-config with a stub pc file to generate the data.
-Not entirely sure the motivation for this - it would be more "isolated"
-to just paste in the data and not depend on pkg-config, but presumably
-this test exists because of observed bugs, so leaving alone for now.
-
-Ran into an interesting problem when we spun up a GitHub Windows Action:
-it finds pre-installed Strawberry Perl's pkg-config over the mingw one,
-which is also pre-installed. The Strawberry one is written in pure
-Perl (after getting past the initial batch file), so requires perl.exe,
-which won't be in the SCons env['ENV']['PATH'].  We try to detect it,
-by somewhat hokey means: if pkg-config's path had "strawberry' in it,
-assume we need to add the directory path to our execution env.
-
-It ended up being more portable to use pkg-config's --with-path than
-to set PKG_CONFIG_PATH, because the Windows cmd.exe can't accept
-the standard calling style.
+Now uses a mocked pkg-config to avoid some weird problems,
+but is still a "live" test because we do expansion on $_CPPDEFFLAGS,
+which needs to have been set up with a compiler tool so have something
+to subst into.
 """
 
 import pathlib
+import sys
 
 import TestSCons
 import TestCmd
 
 test = TestSCons.TestSCons()
+_python_ = TestSCons._python_
 
-pkg_config_path = test.where_is('pkg-config')
-if not pkg_config_path:
-    test.skip_test("Could not find 'pkg-config' in PATH, skipping test.\n")
-pkg_config_path = pkg_config_path.replace("\\", "/")
-
-# Try to guess if this was Strawberry Perl's pkg-config
-if 'strawberry' in pkg_config_path.lower():
-    # as_posix() or the pasted paths in SConstruct will have escape problems
-    # (or need to be raw strings)
-    strawberry_perl_path = pathlib.PurePath(pkg_config_path).parent.as_posix()
-else:
-    strawberry_perl_path = ""
-
-test.write('bug.pc', """\
-prefix=/usr
-exec_prefix=${prefix}
-libdir=${exec_prefix}/lib
-includedir=${prefix}/include
-
-Name: bug
-Description: A test case .pc file
-Version: 1.2
-Cflags: -DSOMETHING -DVARIABLE=2
+mock_pkg_config = test.workpath('mock-pkg-config.py')
+test.write(mock_pkg_config, f"""\
+import sys
+if '--cflags' in sys.argv:
+    print("-DSOMETHING -DVARIABLE=2")
+sys.exit(0)
 """)
 
-test.write('main.c', """\
-int main(int argc, char *argv[])
-{
-  return 0;
-}
-""")
+# Since the mock pkg-config is a Python script, use the selected Python to
+# run it to avoid execution problems (esp. on Windows)
+pc_path = (_python_ + ' ' + mock_pkg_config).replace("\\", "/")
 
+# We need a toolset:
 if TestCmd.IS_WINDOWS:
-    pkg_config_file = 'bug'
-    pkg_config_tools = 'mingw'
+    pc_tools = 'mingw'
 else:
-    pkg_config_file = 'bug.pc'
-    pkg_config_tools = 'default'
-pkg_config_cl_path = '--with-path=.'
+    pc_tools = 'default'
+
+# these are no longer really needed, leave so it looks like a "real" pkg-config
+pc_file = 'bug'
+pc_cl_path = ""
 
 test.write('SConstruct', f"""\
 import os
@@ -98,57 +70,26 @@
 DefaultEnvironment(tools=[])
 # https://github.com/SCons/scons/issues/2671
 # Passing test cases
-env_1 = Environment(
-    CPPDEFINES=[('DEBUG', '1'), 'TEST'],
-    tools=['{pkg_config_tools}']
-)
-if '{strawberry_perl_path}':
-    env_1.AppendENVPath('PATH', '{strawberry_perl_path}')
-if sys.platform == 'win32':
-    os.environ['PKG_CONFIG_PATH'] = env_1.Dir('.').abspath.replace("\\\\", "/")
-env_1.ParseConfig('"{pkg_config_path}" {pkg_config_cl_path} --cflags {pkg_config_file}')
+env_1 = Environment(CPPDEFINES=[('DEBUG', '1'), 'TEST'], tools=['{pc_tools}'])
+env_1.ParseConfig('{pc_path} {pc_cl_path} --cflags {pc_file}')
 print(env_1.subst('$_CPPDEFFLAGS'))
 
-env_2 = Environment(
-    CPPDEFINES=[('DEBUG', '1'), 'TEST'],
-    tools=['{pkg_config_tools}']
-)
-if '{strawberry_perl_path}':
-    env_2.AppendENVPath('PATH', '{strawberry_perl_path}')
+env_2 = Environment(CPPDEFINES=[('DEBUG', '1'), 'TEST'], tools=['{pc_tools}'])
 env_2.MergeFlags('-DSOMETHING -DVARIABLE=2')
 print(env_2.subst('$_CPPDEFFLAGS'))
 
 # Failing test cases
-env_3 = Environment(
-    CPPDEFINES=dict([('DEBUG', 1), ('TEST', None)]),
-    tools=['{pkg_config_tools}'],
-)
-if '{strawberry_perl_path}':
-    env_3.AppendENVPath('PATH', '{strawberry_perl_path}')
-env_3.ParseConfig('"{pkg_config_path}" {pkg_config_cl_path} --cflags {pkg_config_file}')
+env_3 = Environment(CPPDEFINES=dict([('DEBUG', 1), ('TEST', None)]), tools=['{pc_tools}'])
+env_3.ParseConfig('{pc_path} {pc_cl_path} --cflags {pc_file}')
 print(env_3.subst('$_CPPDEFFLAGS'))
 
-env_4 = Environment(
-    CPPDEFINES=dict([('DEBUG', 1), ('TEST', None)]),
-    tools=['{pkg_config_tools}'],
-)
-if '{strawberry_perl_path}':
-    env_4.AppendENVPath('PATH', '{strawberry_perl_path}')
+env_4 = Environment(CPPDEFINES=dict([('DEBUG', 1), ('TEST', None)]), tools=['{pc_tools}'])
 env_4.MergeFlags('-DSOMETHING -DVARIABLE=2')
 print(env_4.subst('$_CPPDEFFLAGS'))
 
 # https://github.com/SCons/scons/issues/1738
-# TODO: the Perl pkg-config doesn't work right with both --cflags --libs
-#   e.g.: pkg-config --with-path=. --libs --cflags bug
-#   Exepct: -DSOMETHING -DVARIABLE=2
-#   Strawberry:   (blank)
-#   We don't have any libs in the stub pc file, so just drop that for now.
-env_1738_1 = Environment(tools=['{pkg_config_tools}'])
-if '{strawberry_perl_path}':
-    env_1738_1.AppendENVPath('PATH', '{strawberry_perl_path}')
-env_1738_1.ParseConfig(
-    '"{pkg_config_path}" {pkg_config_cl_path} --cflags {pkg_config_file}'
-)
+env_1738_1 = Environment(tools=['{pc_tools}'])
+env_1738_1.ParseConfig('{pc_path} {pc_cl_path} --cflags {pc_file}')
 env_1738_1.Append(CPPDEFINES={{'value': '1'}})
 print(env_1738_1.subst('$_CPPDEFFLAGS'))
 """)