Merge pull request #61352 from dims/stabilize-openstack-test-when-running-against-real-openstack-cloud

Automatic merge from submit-queue (batch tested with PRs 60373, 61098, 61352, 61359, 61362). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Stabilize openstack_test when running against real cloud

**What this PR does / why we need it**:

in TestReadConfig, we are setting some env vars for testing if
we read them back properly. However this interferes with running
the unit test harness against a real openstack cloud where we
source the OS_* environment variables. Adding code here to save
and reset variables.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

pkg/cloudprovider/providers/openstack/openstack_test.go

@@ -88,6 +88,11 @@ func TestReadConfig(t *testing.T) {
 		t.Errorf("Should fail when no config is provided: %s", err)
 	}
 
+	// Since we are setting env vars, we need to reset old
+	// values for other tests to succeed.
+	env := clearEnviron(t)
+	defer resetEnviron(t, env)
+
 	os.Setenv("OS_PASSWORD", "mypass")
 	defer os.Unsetenv("OS_PASSWORD")
 
@@ -681,3 +686,24 @@ func TestToAuth3Options(t *testing.T) {
 		t.Errorf("DomainName %s != %s", ao.DomainName, cfg.Global.DomainName)
 	}
 }
+
+func clearEnviron(t *testing.T) []string {
+	env := os.Environ()
+	for _, pair := range env {
+		if strings.HasPrefix(pair, "OS_") {
+			i := strings.Index(pair, "=") + 1
+			os.Unsetenv(pair[:i-1])
+		}
+	}
+	return env
+}
+func resetEnviron(t *testing.T, items []string) {
+	for _, pair := range items {
+		if strings.HasPrefix(pair, "OS_") {
+			i := strings.Index(pair, "=") + 1
+			if err := os.Setenv(pair[:i-1], pair[i:]); err != nil {
+				t.Errorf("Setenv(%q, %q) failed during reset: %v", pair[:i-1], pair[i:], err)
+			}
+		}
+	}
+}