diff --git a/emulator/Makefile b/emulator/Makefile
index 70a45ee5..897b83e1 100644
--- a/emulator/Makefile
+++ b/emulator/Makefile
@@ -10,7 +10,7 @@ all: emulator-$(CONFIG)
 debug: emulator-$(CONFIG)-debug
 
 include $(base_dir)/Makefrag
--include generated-src/Makefrag
+-include generated-src/Makefrag-tests.$(CONFIG)
 
 CXXFLAGS := $(CXXFLAGS) -std=c++11 -I$(RISCV)/include
 
diff --git a/fsim/Makefile b/fsim/Makefile
index 5b3ecc7a..80a5767a 100644
--- a/fsim/Makefile
+++ b/fsim/Makefile
@@ -21,7 +21,7 @@ TB ?= rocketTestHarness
 
 include $(base_dir)/Makefrag
 include $(sim_dir)/Makefrag
--include $(generated_dir)/Makefrag
+-include $(generated_dir)/Makefrag-tests.$(CONFIG)
 include $(base_dir)/vsim/Makefrag-sim
 
 all: $(simv)
diff --git a/src/main/scala/Testing.scala b/src/main/scala/Testing.scala
index 9edb4c3c..eed35c72 100644
--- a/src/main/scala/Testing.scala
+++ b/src/main/scala/Testing.scala
@@ -66,7 +66,7 @@ run-$kind-fast: $$(addprefix $$(output_dir)/, $$(addsuffix .run, $targets))
       } else { "\n" }
     }
 
-    val f = createOutputFile("Makefrag")
+    val f = createOutputFile("Makefrag-tests." + Driver.chiselConfigClassName.get)
     f.write(List(gen("asm", asmSuites.values.toSeq), gen("bmark", bmarkSuites.values.toSeq)).mkString("\n"))
     f.close
   }
diff --git a/vsim/Makefile b/vsim/Makefile
index e7a52ae7..013d2f5b 100644
--- a/vsim/Makefile
+++ b/vsim/Makefile
@@ -21,7 +21,7 @@ TB ?= rocketTestHarness
 
 include $(base_dir)/Makefrag
 include $(sim_dir)/Makefrag
--include $(generated_dir)/Makefrag
+-include $(generated_dir)/Makefrag-tests.$(CONFIG)
 include $(base_dir)/vsim/Makefrag-sim
 
 all: $(simv)