diff --git a/.github/workflows/scala.yml b/.github/workflows/scala.yml
index 64a3fbf24..9be25e2a7 100644
--- a/.github/workflows/scala.yml
+++ b/.github/workflows/scala.yml
@@ -68,7 +68,11 @@ jobs:
 
     - name: Build and test with coverage
       shell: bash
-      run: sbt -v coverage +test coverageReport coverageAggregate jacocoAggregate
+      run: |
+        sbt -v coverage testAggregate/test \
+          testAggregate/coverageReport \
+          coverageAggregate \
+          jacocoAggregate
 
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@v5
diff --git a/build.sbt b/build.sbt
index f282b80ad..5802465e4 100644
--- a/build.sbt
+++ b/build.sbt
@@ -551,3 +551,24 @@ lazy val grpc = (project in file("pekko-grpc"))
   )
   .dependsOn(stream)
   .dependsOn(core % "compile->compile;test->test")
+
+// Aggregated project for generating correct test coverage reports, including
+// cross-module tests.
+lazy val testAggregate = (project in file("."))
+  .aggregate(
+    core,
+    corePatch,
+    jena,
+    jenaPatch,
+    rdf4j,
+    rdf4jPatch,
+    titaniumRdfApi,
+    stream,
+    integrationTests,
+    examples,
+    grpc,
+  )
+  .settings(
+    name := "jelly-jvm",
+    publishArtifact := false,
+  )