fix: stop coverage without start

Browser/keywords/coverage.py

@@ -20,7 +20,7 @@
 
 from ..base import LibraryComponent
 from ..generated.playwright_pb2 import Request
-from ..utils import CoverageType, keyword, logger
+from ..utils import ROBOT_FRAMEWORK_BROWSER_NO_SET, CoverageType, keyword, logger
 
 
 class Coverage(LibraryComponent):
@@ -89,20 +89,23 @@ def start_coverage(
     @keyword(tags=("Getter", "Coverage"))
     def stop_coverage(
         self,
-    ) -> Path:
+    ) -> Path | None:
         """Stops the coverage for the current page.
 
         Creates a coverage report by using
         [https://www.npmjs.com/package/monocart-coverage-reports|monocart-coverage-reports]
         To see the default and all possible options, see
         [https://github.com/cenfun/monocart-coverage-reports/blob/HEAD/lib/default/options.js|options.js]
         file for more details. Returns the path to the folder where
-        coverage reported.
+        coverage reported if coverage was started, otherwise returns `None`.
         """
         logger.info("Stopping coverage")
         with self.playwright.grpc_channel() as stub:
             response = stub.StopCoverage(Request.Empty())
-            logger.info(response.log)
+        logger.info(response.log)
+        if response.body == ROBOT_FRAMEWORK_BROWSER_NO_SET:
+            logger.info("Coverage was not started, no report generated.")
+            return None
         coverage_dir = Path(response.body)
         coverage_index_html = list(coverage_dir.glob("*.html"))
         if not coverage_index_html:

atest/test/01_Browser_Management/coverage.robot

@@ -269,6 +269,14 @@ Merge Coverage Reports Invalid Config File
         Log    Caught expected error ${error}
     END
 
+Only Stop Coverage
+    [Documentation]    ...
+    ...    LOG 1:2    INFO    Stopping coverage
+    ...    LOG 1:3    INFO    Coverage not started
+    ...    LOG 1:4    INFO    Coverage was not started, no report generated.
+    ${result} =    Stop Coverage
+    Should Be Equal    ${result}    ${None}
+
 *** Keywords ***
 Open Page And Store ID
     &{page_info} =    New Page

node/playwright-wrapper/playwright-state.ts

@@ -1166,7 +1166,7 @@ async function _saveCoverageReport(activeIndexedPage: IndexedPage): Promise<Resp
     const { coverage: coverageOptions, p: activePage, id: pageId } = activeIndexedPage;
     activeIndexedPage.coverage = undefined;
     if (!coverageOptions) {
-        return stringResponse('', 'Coverage not started');
+        return stringResponse('ROBOT_FRAMEWORK_BROWSER_NO_SET', 'Coverage not started');
     }
     const { directory: coverageDir = '', configFile = '', type: coverageType, raw = false } = coverageOptions;