include useful output logs for failing tests

This helps when tests fail on the gitlab-ci builds.

app/build.gradle

@@ -157,8 +157,17 @@ android {
     }
 
     testOptions {
+        unitTests {
             // prevent tests from dying on android.util.Log calls
-        unitTests.returnDefaultValues = true
+            returnDefaultValues = true
+            all {
+                // All the usual Gradle options.
+                testLogging {
+                    events "skipped", "failed", "standardOut", "standardError"
+                    showStandardStreams = true
+                }
+            }
+        }
     }
 
     lintOptions {