chore(tests): limit number of builds in test_before_all

Author: mayeut

test/test_before_all.py

@@ -10,13 +10,22 @@
 project_with_before_build_asserts = test_projects.new_c_project(
     setup_py_add=textwrap.dedent(
         r"""
-        # assert that the Python version as written to text_info.txt in the CIBW_BEFORE_ALL step
-        # is the same one as is currently running.
+        import os
+
         with open("text_info.txt") as f:
             stored_text = f.read()
-
         print("## stored text: " + stored_text)
         assert stored_text == "sample text 123"
+
+        # assert that the Python version as written to python_prefix.txt in the CIBW_BEFORE_ALL step
+        # is not the same one as is currently running.
+        with open('python_prefix.txt') as f:
+            stored_prefix = f.read()
+        print('stored_prefix', stored_prefix)
+        print('sys.prefix', sys.prefix)
+        #  Works around path-comparison bugs caused by short-paths on Windows e.g.
+        #  vssadm~1 instead of vssadministrator
+        assert os.stat(stored_prefix) != os.stat(sys.prefix)
         """
     )
 )
@@ -30,21 +39,24 @@ def test(tmp_path):
         print("dummy text", file=ff)
 
     # build the wheels
-    before_all_command = '''python -c "import os;open('{project}/text_info.txt', 'w').write('sample text '+os.environ.get('TEST_VAL', ''))"'''
+    before_all_command = (
+        """python -c "import os, sys;open('{project}/text_info.txt', 'w').write('sample text '+os.environ.get('TEST_VAL', ''))" && """
+        '''python -c "import sys; open('{project}/python_prefix.txt', 'w').write(sys.prefix)"'''
+    )
     actual_wheels = utils.cibuildwheel_run(
         project_dir,
         add_env={
             # write python version information to a temporary file, this is
             # checked in setup.py
             "CIBW_BEFORE_ALL": before_all_command,
-            "CIBW_BEFORE_ALL_LINUX": f'{before_all_command} && python -c "import sys; assert sys.version_info >= (3, 6)"',
+            "CIBW_BEFORE_ALL_LINUX": f'{before_all_command} && python -c "import sys; assert sys.version_info >= (3, 8)"',
             "CIBW_ENVIRONMENT": "TEST_VAL='123'",
         },
+        single_python=True,
     )
 
     # also check that we got the right wheels
-    (project_dir / "text_info.txt").unlink()
-    expected_wheels = utils.expected_wheels("spam", "0.1.0")
+    expected_wheels = utils.expected_wheels("spam", "0.1.0", single_python=True)
     assert set(actual_wheels) == set(expected_wheels)