source: add a default value for search_drivers in POST /source

subiquity/common/apidef.py

@@ -145,7 +145,7 @@ def GET(index: Optional[str]) -> AnyStep: ...
 
     class source:
         def GET() -> SourceSelectionAndSetting: ...
-        def POST(source_id: str, search_drivers: bool) -> None: ...
+        def POST(source_id: str, search_drivers: bool = False) -> None: ...
 
     class zdev:
         def GET() -> List[ZdevInfo]: ...

subiquity/server/controllers/source.py

@@ -126,7 +126,8 @@ async def configured(self):
         await super().configured()
         self.app.base_model.set_source_variant(self.model.current.variant)
 
-    async def POST(self, source_id: str, search_drivers: bool) -> None:
+    async def POST(self, source_id: str,
+                   search_drivers: bool = False) -> None:
         self.model.search_drivers = search_drivers
         for source in self.model.sources:
             if source.id == source_id:

subiquity/tests/api/test_api.py

@@ -1041,3 +1041,21 @@ async def test_cancel_drivers(self):
                 # should not raise ServerDisconnectedError
                 resp = await inst.get('/drivers', wait=True)
                 self.assertEqual(['nvidia-driver-470-server'], resp['drivers'])
+
+
+class TestSource(TestAPI):
+    async def test_optional_search_drivers(self):
+        async with start_server('examples/simple.json') as inst:
+            await inst.post('/source', source_id='ubuntu-server')
+            resp = await inst.get('/source')
+            self.assertFalse(resp['search_drivers'])
+
+            await inst.post('/source', source_id='ubuntu-server',
+                            search_drivers=True)
+            resp = await inst.get('/source')
+            self.assertTrue(resp['search_drivers'])
+
+            await inst.post('/source', source_id='ubuntu-server',
+                            search_drivers=False)
+            resp = await inst.get('/source')
+            self.assertFalse(resp['search_drivers'])