Fix TestMissingScores NullReferenceException and parallelize CI test matrix

ResultsScreen.cs: GetBeatmapAsync can return null when the online ID is unknown
(e.g. in the TestMissingScores test which returns empty scores). Replace the
null-forgiving ! with a proper ??= placeholder matching the SubScreenBeatmapSelect
pattern. Fixes the Linux test-results reporter failure.

ci.yml: Split the test matrix into two parallel groups per OS (game: osu.Game.Tests
+ Tournament + Templates; rulesets: 4 ruleset DLLs). Each group runs in ~half the
total time, so Windows runners (~2-3× slower than Linux) complete each group in
~60 min instead of exceeding the 120 min wall-clock budget for the full suite.
Per-job timeout reduced from 120 → 90 min (right-sized for a single group).

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/4f0e240e-6ec5-4f03-abaf-c0a6e6e7a448

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: Copilot

.github/workflows/ci.yml

@@ -87,7 +87,21 @@ jobs:
             # - { prettyname: macOS, fullname: macos-latest }
             - { prettyname: Linux, fullname: ubuntu-latest }
           threadingMode: ['MultiThreaded']
-    timeout-minutes: 120
+          # Split tests into two parallel groups so Windows runners (which are ~2-3× slower than
+          # Linux) finish each group in ~60 min rather than timing out on the full suite at 120 min.
+          testSuite:
+            - name: game
+              dlls: >-
+                osu.Game.Tests/bin/Debug/**/osu.Game.Tests.dll
+                osu.Game.Tournament.Tests/bin/Debug/**/osu.Game.Tournament.Tests.dll
+                Templates/**/*.Tests/bin/Debug/**/*.Tests.dll
+            - name: rulesets
+              dlls: >-
+                osu.Game.Rulesets.Osu.Tests/bin/Debug/**/osu.Game.Rulesets.Osu.Tests.dll
+                osu.Game.Rulesets.Taiko.Tests/bin/Debug/**/osu.Game.Rulesets.Taiko.Tests.dll
+                osu.Game.Rulesets.Catch.Tests/bin/Debug/**/osu.Game.Rulesets.Catch.Tests.dll
+                osu.Game.Rulesets.Mania.Tests/bin/Debug/**/osu.Game.Rulesets.Mania.Tests.dll
+    timeout-minutes: 90
     steps:
       - name: Checkout
         uses: actions/checkout@v6
@@ -116,14 +130,8 @@ jobs:
         continue-on-error: true
         run: >
           dotnet test
-          osu.Game.Tests/bin/Debug/**/osu.Game.Tests.dll
-          osu.Game.Rulesets.Osu.Tests/bin/Debug/**/osu.Game.Rulesets.Osu.Tests.dll
-          osu.Game.Rulesets.Taiko.Tests/bin/Debug/**/osu.Game.Rulesets.Taiko.Tests.dll
-          osu.Game.Rulesets.Catch.Tests/bin/Debug/**/osu.Game.Rulesets.Catch.Tests.dll
-          osu.Game.Rulesets.Mania.Tests/bin/Debug/**/osu.Game.Rulesets.Mania.Tests.dll
-          osu.Game.Tournament.Tests/bin/Debug/**/osu.Game.Tournament.Tests.dll
-          Templates/**/*.Tests/bin/Debug/**/*.Tests.dll
-          --logger "trx;LogFileName=TestResults-${{matrix.os.prettyname}}-${{matrix.threadingMode}}.trx"
+          ${{matrix.testSuite.dlls}}
+          --logger "trx;LogFileName=TestResults-${{matrix.os.prettyname}}-${{matrix.threadingMode}}-${{matrix.testSuite.name}}.trx"
           --
           NUnit.ConsoleOut=0
 
@@ -133,8 +141,8 @@ jobs:
         uses: actions/upload-artifact@v7
         if: ${{ !cancelled() }}
         with:
-          name: osu-test-results-${{matrix.os.prettyname}}-${{matrix.threadingMode}}
-          path: ${{github.workspace}}/TestResults/TestResults-${{matrix.os.prettyname}}-${{matrix.threadingMode}}.trx
+          name: osu-test-results-${{matrix.os.prettyname}}-${{matrix.threadingMode}}-${{matrix.testSuite.name}}
+          path: ${{github.workspace}}/TestResults/TestResults-${{matrix.os.prettyname}}-${{matrix.threadingMode}}-${{matrix.testSuite.name}}.trx
 
   test-results:
     name: Test results

osu.Game/Screens/OnlinePlay/Matchmaking/RankedPlay/ResultsScreen.cs

@@ -125,7 +125,19 @@ private async Task fetchFinalScores()
                 };
 
                 // Should complete instantaneously due to prior lookups.
-                APIBeatmap beatmap = (await beatmapLookupCache.GetBeatmapAsync(globalBeatmap.Value.BeatmapInfo.OnlineID).ConfigureAwait(false))!;
+                // GetBeatmapAsync can return null if the online ID is unknown (e.g. in tests or
+                // when the API is unavailable); fall back to a placeholder rather than crashing.
+                APIBeatmap? beatmap = await beatmapLookupCache.GetBeatmapAsync(globalBeatmap.Value.BeatmapInfo.OnlineID).ConfigureAwait(false);
+                beatmap ??= new APIBeatmap
+                {
+                    BeatmapSet = new APIBeatmapSet
+                    {
+                        Title = "unknown beatmap",
+                        TitleUnicode = "unknown beatmap",
+                        Artist = "unknown artist",
+                        ArtistUnicode = "unknown artist",
+                    }
+                };
 
                 Schedule(() =>
                 {