chore(folio): a just recipe for the unit tests

examples/folio/justfile

@@ -78,6 +78,13 @@ _ensure-device:
     echo "emulator did not finish booting in time (see /tmp/folio-emulator.log)" >&2
     exit 1
 
+# Run folio's own unit tests. Named test-unit because `test` is the fuzz run.
+test-unit:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    export ANDROID_HOME="$(just _android-home)"
+    ./gradlew :core:testDebugUnitTest :app:shared:testDebugUnitTest
+
 # Build the folio debug APK without installing it.
 build:
     #!/usr/bin/env bash