exec-test clear testing environment

This commit adds more control over the environment variables in
exec-tests for users. It brings a way how to clear the test environment
during the test runtime so it won't affect the test script. Only thing
which user needs to do is to set the runner.exectest.clear_env to `true`
in tests config.

Reference: avocado-framework#5889
Signed-off-by: Jan Richter <[email protected]>

avocado/core/__init__.py

@@ -178,6 +178,18 @@ def register_core_options():
         help_msg=help_msg,
     )
 
+    help_msg = (
+        "Whether to run the exec-test with an empty environment "
+        "(no variables set, besides avocado's default and kwargs)"
+    )
+    stgs.register_option(
+        section="runner.exectest",
+        key="clear_env",
+        key_type=bool,
+        default=False,
+        help_msg=help_msg,
+    )
+
     help_msg = (
         "By default Avocado runners will use the {uri} of a test as "
         "its identifier. Use a custom f-string identifier in order to "

avocado/plugins/runners/exec_test.py

@@ -33,7 +33,11 @@ class ExecTestRunner(BaseRunner):
     name = "exec-test"
     description = "Runner for standalone executables treated as tests"
 
-    CONFIGURATION_USED = ["run.keep_tmp", "runner.exectest.exitcodes.skip"]
+    CONFIGURATION_USED = [
+        "run.keep_tmp",
+        "runner.exectest.exitcodes.skip",
+        "runner.exectest.clear_env",
+    ]
 
     def _process_final_status(
         self, process, runnable, stdout=None, stderr=None
@@ -119,7 +123,11 @@ def _is_uri_a_file_on_cwd(uri):
         return False
 
     def _get_env(self, runnable):
-        env = dict(os.environ)
+        clear_env = runnable.config.get("runner.exectest.clear_env", False)
+        if clear_env:
+            env = {}
+        else:
+            env = dict(os.environ)
         if runnable.kwargs:
             env.update(runnable.kwargs)
             for key, value in runnable.kwargs.items():

docs/source/guides/writer/chapters/basics.rst

@@ -99,3 +99,10 @@ disable those variables during the test runtime. To disable a test variable,
 you need to set it in test ``kwargs`` to ``None``  like this::
 
   Runnable("exec-test", "examples/tests/sleeptest.sh", SLEEP_LENGTH=None)
+
+If you need to clear the whole environment before your test, then you can set
+``runner.exectest.clear_env`` config variable to ``True``. When this variable is set, avocado will clear
+the entire environment during the test runtime and keeps only avocado env variables
+and variables from test's ``kwargs``::
+
+  Runnable("exec-test", "examples/tests/sleeptest.sh", config={'runner.exectest.clear_env': True}, SLEEP_LENGTH=1)

selftests/check.py

@@ -29,7 +29,7 @@
     "nrunner-requirement": 16,
     "unit": 669,
     "jobs": 11,
-    "functional-parallel": 303,
+    "functional-parallel": 304,
     "functional-serial": 4,
     "optional-plugins": 0,
     "optional-plugins-golang": 2,

selftests/functional/basic.py

@@ -1116,6 +1116,21 @@ def test_env_var_disable(self):
                 "'returncode': 0", result, "The env variable was not disabled."
             )
 
+    @skipUnlessPathExists("/bin/sh")
+    def test_env_clear(self):
+        with script.TemporaryScript("exec_env_var.sh", EXEC_ENV_VARIABLE_TEST) as tst:
+            res = process.run(
+                f"env TEST_ENV=test avocado-runner-exec-test runnable-run -k exec-test -u {tst}"
+            )
+            result = res.stdout_text.split("\n")[-2]
+            self.assertIn("'returncode': 1", result, "The test might be corrupted.")
+
+            res = process.run(
+                f"env TEST_ENV=test avocado-runner-exec-test runnable-run -k exec-test -u {tst} -c '{{\"runner.exectest.clear_env\": true}}'"
+            )
+            result = res.stdout_text.split("\n")[-2]
+            self.assertIn("'returncode': 0", result, "The environment was not cleared.")
+
     def tearDown(self):
         self.pass_script.remove()
         self.fail_script.remove()