diff --git a/Makefile b/Makefile
index 448c27665ab..71583081102 100644
--- a/Makefile
+++ b/Makefile
@@ -27,9 +27,9 @@ makefiles += \
   src/libstore/tests/local.mk \
   src/libexpr/tests/local.mk \
   tests/local.mk \
-  tests/overlay-local-store/local.mk \
   tests/ca/local.mk \
   tests/dyn-drv/local.mk \
+  tests/overlay-local-store/local.mk \
   tests/test-libstoreconsumer/local.mk \
   tests/plugins/local.mk
 else
diff --git a/doc/manual/src/contributing/testing.md b/doc/manual/src/contributing/testing.md
index b2add42c3d1..c3c82e3c058 100644
--- a/doc/manual/src/contributing/testing.md
+++ b/doc/manual/src/contributing/testing.md
@@ -28,7 +28,8 @@ ran test tests/bar.sh... [PASS]
 ### Grouping tests
 
 Sometimes it is useful to group related tests so they can be easily run together without running the entire test suite.
-For example, `tests/ca/local.mk` defines a "ca" test group for tests relating to content-addressed derivation outputs.
+Each test group is in a subdirectory of `tests`.
+For example, `tests/ca/local.mk` defines a `ca` test group for content-addressed derivation outputs.
 
 That test group can be run like this:
 
@@ -39,7 +40,7 @@ ran test tests/ca/import-derivation.sh... [PASS]
 ...
 ```
 
-The testgroup is defined in Make like this:
+The test group is defined in Make like this:
 ```makefile
 $(test-group-name)-tests := \
   $(d)/test0.sh \
diff --git a/mk/lib.mk b/mk/lib.mk
index cddaf9eb12d..e86a7f1a448 100644
--- a/mk/lib.mk
+++ b/mk/lib.mk
@@ -161,6 +161,14 @@ ifdef libs-list
 	@echo "The following libraries can be built:"
 	@echo ""
 	@for i in $(libs-list); do echo "  $$i"; done
+endif
+ifdef install-tests-groups
+	@echo ""
+	@echo "The following groups of functional tests can be run:"
+	@echo ""
+	@for i in $(install-tests-groups); do echo "  $$i.test-group"; done
+	@echo ""
+	@echo "(installcheck includes tests in test groups too.)"
 endif
 	@echo ""
 	@echo "The following variables control the build:"