diff --git a/sbt/src/sbt-test/tests/empty/build.sbt b/sbt/src/sbt-test/tests/empty/build.sbt
new file mode 100644
index 000000000..9d367c12a
--- /dev/null
+++ b/sbt/src/sbt-test/tests/empty/build.sbt
@@ -0,0 +1,8 @@
+testGrouping <<= (definedTests in Test) map { tests =>
+      tests map { test =>
+        new Tests.Group(
+          name = test.name,
+          tests = Seq(test),
+          runPolicy = Tests.SubProcess(javaOptions = Seq.empty[String]))
+      }
+    }
diff --git a/sbt/src/sbt-test/tests/empty/test b/sbt/src/sbt-test/tests/empty/test
new file mode 100644
index 000000000..c0117a9ba
--- /dev/null
+++ b/sbt/src/sbt-test/tests/empty/test
@@ -0,0 +1,3 @@
+# https://github.com/sbt/sbt/issues/777
+# throws an exception for custom groupings when no tests are defined
+> test