test(plugin): cover leading empty entry in HELM_PLUGINS

Adds a TestPath case where the list begins with the separator so the first non-empty directory is chosen.

Signed-off-by: Yuhui Luo <92632263+lyh7c00@users.noreply.github.com>

internal/plugin/installer/base_test.go

@@ -39,6 +39,10 @@ func TestPath(t *testing.T) {
 			source:         "https://github.com/jkroepke/helm-secrets",
 			helmPluginsDir: strings.Join([]string{"/helm/data/plugins", "/helm/data/extra"}, string(filepath.ListSeparator)),
 			expectPath:     "/helm/data/plugins/helm-secrets",
+		}, {
+			source:         "https://github.com/jkroepke/helm-secrets",
+			helmPluginsDir: string(filepath.ListSeparator) + "/helm/data/plugins",
+			expectPath:     "/helm/data/plugins/helm-secrets",
 		},
 	}