test cases: use best practices method to find the python3 program

We do not need the python module's find_installation() for this, as this
does various things to set up building and installing python modules
(pure python and C-API). This functionality is already tested in the
python tests.

Elsewhere, when we just need an interpreter capable of running python
scripts in order to guarantee a useful scripting language for custom
commands, it suffices to use find_program(), which does not run an
introspection script or do module imports, and is thus faster and
a bit cleaner.

Either way, both methods are guaranteed to find the python3 interpreter,
deferring to mesonlib.python_command for that guarantee.

test "71 summary" can sometimes return the python command with the
".exe" part all uppercased for mysterious Windows reasons. Smooth this
over with ExternalProgram.

6 files changed, 6 insertions, 5 deletions

diff --git a/test cases/unit/64 alias target/meson.build b/test cases/unit/64 alias target/meson.build
index bcd4005f4..197897b5f 100644
--- a/test cases/unit/64 alias target/meson.build
+++ b/test cases/unit/64 alias target/meson.build
@@ -1,6 +1,6 @@
 project('alias target', 'c')
 
-python3 = import('python').find_installation()
+python3 = find_program('python3')
 
 exe_target = executable('prog', 'main.c',
   build_by_default : false)
diff --git a/test cases/unit/70 cross test passed/meson.build b/test cases/unit/70 cross test passed/meson.build
index 4deb74baf..3a09a7771 100644
--- a/test cases/unit/70 cross test passed/meson.build
+++ b/test cases/unit/70 cross test passed/meson.build
@@ -6,7 +6,7 @@ project(
 
 e = executable('exec', 'src/main.c')
 
-py = import('python').find_installation()
+py = find_program('python3')
 
 test('root', e)
 test('main', py, args : [meson.current_source_dir() / 'script.py', e])
diff --git a/test cases/unit/71 summary/meson.build b/test cases/unit/71 summary/meson.build
index ce97fb376..76fc545f4 100644
--- a/test cases/unit/71 summary/meson.build
+++ b/test cases/unit/71 summary/meson.build
@@ -11,7 +11,7 @@ summary({'Some boolean': false,
          'enabled_opt': get_option('enabled_opt'),
         }, section: 'Configuration')
 summary({'missing prog': find_program('xyzzy', required: false),
-         'existing prog': import('python').find_installation(),
+         'existing prog': find_program(get_option('python')).full_path(),
          'missing dep': dependency('', required: false),
          'external dep': dependency('zlib', required: false),
          'internal dep': declare_dependency(),
diff --git a/test cases/unit/71 summary/meson_options.txt b/test cases/unit/71 summary/meson_options.txt
index 281c3b672..cf3f32c90 100644
--- a/test cases/unit/71 summary/meson_options.txt
+++ b/test cases/unit/71 summary/meson_options.txt
@@ -1 +1,2 @@
 option('enabled_opt', type: 'feature', value: 'auto')
+option('python', type: 'string')
diff --git a/test cases/unit/73 dep files/meson.build b/test cases/unit/73 dep files/meson.build
index 4829f563f..af7f6e47b 100644
--- a/test cases/unit/73 dep files/meson.build
+++ b/test cases/unit/73 dep files/meson.build
@@ -1,6 +1,6 @@
 project('test', 'c')
 
-python = import('python').find_installation()
+python = find_program('python3')
 
 lib = library('foo', 'foo.c')
 
diff --git a/test cases/unit/99 custom target name/meson.build b/test cases/unit/99 custom target name/meson.build
index 8d148a88d..82876149f 100644
--- a/test cases/unit/99 custom target name/meson.build
+++ b/test cases/unit/99 custom target name/meson.build
@@ -1,6 +1,6 @@
 project('custom target name', 'c')
 
-python = import('python').find_installation()
+python = find_program('python3')
 
 # Name argument is optional and should default to 'file.txt'
 custom_target(