diff --git a/Makefile b/Makefile
index d24848bf..5a9cd2cb 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,7 @@
 # Version and build configuration variables
 BUILD_CONFIGURATION ?= debug
 WARNINGS_AS_ERRORS ?= true
-SWIFT_CONFIGURATION := $(if $(filter-out false,$(WARNINGS_AS_ERRORS)),-Xswiftc -warnings-as-errors)
+SWIFT_CONFIGURATION := $(if $(filter-out false,$(WARNINGS_AS_ERRORS)),-Xswiftc -warnings-as-errors) -Xswiftc -enable-testing
 # Code-coverage instrumentation, layered onto the shared build stages. Empty for
 # ordinary builds; the coverage-* targets opt in via a target-specific value so
 # only those goals compile instrumented binaries.
@@ -173,7 +173,7 @@ dsym:
 
 .PHONY: test
 test: build-tests
-	@$(SWIFT) test -c $(BUILD_CONFIGURATION) $(SWIFT_CONFIGURATION) --skip TestCLI --skip IntegrationTests
+	@$(SWIFT) test --skip-build -c $(BUILD_CONFIGURATION) $(SWIFT_CONFIGURATION) --skip TestCLI --skip IntegrationTests
 
 .PHONY: install-kernel
 install-kernel: