diff --git a/tests/axi/Makefile b/tests/axi/Makefile
index 21e710d..8f769e5 100644
--- a/tests/axi/Makefile
+++ b/tests/axi/Makefile
@@ -42,8 +42,6 @@ export PARAM_BUSER_WIDTH ?= 1
 export PARAM_ARUSER_WIDTH ?= 1
 export PARAM_RUSER_WIDTH ?= 1
 
-SIM_BUILD ?= sim_build_$(MODULE)-$(PARAM_DATA_WIDTH)
-
 ifeq ($(SIM), icarus)
 	PLUSARGS += -fst
 
@@ -79,6 +77,8 @@ else ifeq ($(SIM), verilator)
 	endif
 endif
 
+include $(shell cocotb-config --makefiles)/Makefile.sim
+
 iverilog_dump.v:
 	echo 'module iverilog_dump();' > $@
 	echo 'initial begin' >> $@
@@ -88,9 +88,5 @@ iverilog_dump.v:
 	echo 'endmodule' >> $@
 
 clean::
-	@rm -rf sim_build_*
 	@rm -rf iverilog_dump.v
 	@rm -rf dump.fst $(TOPLEVEL).fst
-
-include $(shell cocotb-config --makefiles)/Makefile.sim
-
diff --git a/tests/axi/test_axi.py b/tests/axi/test_axi.py
index 3235b0d..afe3ba2 100644
--- a/tests/axi/test_axi.py
+++ b/tests/axi/test_axi.py
@@ -338,8 +338,8 @@ def test_axi(request, data_width):
 
     extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()}
 
-    sim_build = os.path.join(tests_dir,
-        "sim_build_"+request.node.name.replace('[', '-').replace(']', ''))
+    sim_build = os.path.join(tests_dir, "sim_build",
+        request.node.name.replace('[', '-').replace(']', ''))
 
     cocotb_test.simulator.run(
         python_search=[tests_dir],
diff --git a/tests/axil/Makefile b/tests/axil/Makefile
index fe95e34..345378d 100644
--- a/tests/axil/Makefile
+++ b/tests/axil/Makefile
@@ -36,8 +36,6 @@ export PARAM_DATA_WIDTH ?= 32
 export PARAM_ADDR_WIDTH ?= 32
 export PARAM_STRB_WIDTH ?= $(shell expr $(PARAM_DATA_WIDTH) / 8 )
 
-SIM_BUILD ?= sim_build_$(MODULE)-$(PARAM_DATA_WIDTH)
-
 ifeq ($(SIM), icarus)
 	PLUSARGS += -fst
 
@@ -61,6 +59,8 @@ else ifeq ($(SIM), verilator)
 	endif
 endif
 
+include $(shell cocotb-config --makefiles)/Makefile.sim
+
 iverilog_dump.v:
 	echo 'module iverilog_dump();' > $@
 	echo 'initial begin' >> $@
@@ -70,9 +70,5 @@ iverilog_dump.v:
 	echo 'endmodule' >> $@
 
 clean::
-	@rm -rf sim_build_*
 	@rm -rf iverilog_dump.v
 	@rm -rf dump.fst $(TOPLEVEL).fst
-
-include $(shell cocotb-config --makefiles)/Makefile.sim
-
diff --git a/tests/axil/test_axil.py b/tests/axil/test_axil.py
index 73da9a0..ae226b7 100644
--- a/tests/axil/test_axil.py
+++ b/tests/axil/test_axil.py
@@ -316,8 +316,8 @@ def test_axil(request, data_width):
 
     extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()}
 
-    sim_build = os.path.join(tests_dir,
-        "sim_build_"+request.node.name.replace('[', '-').replace(']', ''))
+    sim_build = os.path.join(tests_dir, "sim_build",
+        request.node.name.replace('[', '-').replace(']', ''))
 
     cocotb_test.simulator.run(
         python_search=[tests_dir],
diff --git a/tests/axis/Makefile b/tests/axis/Makefile
index 7f91f8b..795f26e 100644
--- a/tests/axis/Makefile
+++ b/tests/axis/Makefile
@@ -38,8 +38,6 @@ export PARAM_ID_WIDTH ?= 8
 export PARAM_DEST_WIDTH ?= 8
 export PARAM_USER_WIDTH ?= 1
 
-SIM_BUILD ?= sim_build_$(MODULE)-$(PARAM_DATA_WIDTH)
-
 ifeq ($(SIM), icarus)
 	PLUSARGS += -fst
 
@@ -67,6 +65,8 @@ else ifeq ($(SIM), verilator)
 	endif
 endif
 
+include $(shell cocotb-config --makefiles)/Makefile.sim
+
 iverilog_dump.v:
 	echo 'module iverilog_dump();' > $@
 	echo 'initial begin' >> $@
@@ -76,9 +76,5 @@ iverilog_dump.v:
 	echo 'endmodule' >> $@
 
 clean::
-	@rm -rf sim_build_*
 	@rm -rf iverilog_dump.v
 	@rm -rf dump.fst $(TOPLEVEL).fst
-
-include $(shell cocotb-config --makefiles)/Makefile.sim
-
diff --git a/tests/axis/test_axis.py b/tests/axis/test_axis.py
index f513121..65bcb1b 100644
--- a/tests/axis/test_axis.py
+++ b/tests/axis/test_axis.py
@@ -170,8 +170,8 @@ def test_axis(request, data_width):
 
     extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()}
 
-    sim_build = os.path.join(tests_dir,
-        "sim_build_"+request.node.name.replace('[', '-').replace(']', ''))
+    sim_build = os.path.join(tests_dir, "sim_build",
+        request.node.name.replace('[', '-').replace(']', ''))
 
     cocotb_test.simulator.run(
         python_search=[tests_dir],