diff --git a/.gitignore b/.gitignore
index 957c3ef..9d496ba 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1 @@
-simtop_*
+tests/test_*
diff --git a/Makefile b/Makefile
deleted file mode 100644
index e69de29..0000000
diff --git a/README.md b/README.md
index 6570060..c31801a 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ License, v.2.0. A copy of this license may be found in the file `COPYING`. You
 can obtain one at https://mozilla.org/MPL/2.0/.
 
 All Verilog source in this project is dual-licensed under the MPL v2.0
-and the CERN-OHL-W v2.0 (or any later version).
+and the CERN-OHL-W v2.0.
 
 ## Tests
 
@@ -18,11 +18,6 @@ Run `./mk.sh` in `tests/` to generate and run tests.
 
 ## Modules
 
-"master_no_read" and "slave_no_write" have no Master In, Slave Out ("miso")
-wires (and no corresponding shift registers), while "master_no_write"
-and "slave_no_read" have no Master Out, Slave In ("mosi") wires. This
-is for compatability for "SPI compatible" devices that are read only.
-
 "master_ss" and others include a timer that will assert the Slave Select
 pin and wait a set number of clock cycles before starting the SPI transfer.
 
diff --git a/spi_master.v b/spi_master.v
index 715ad98..5f478d7 100644
--- a/spi_master.v
+++ b/spi_master.v
@@ -1,7 +1,7 @@
-/* (c) Peter McGoron 2022 v0.4
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v.2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+/* (c) Peter McGoron 2022-2024 v0.4
+ *
+ * This code is disjunctively dual-licensed under the MPL v2.0, or the
+ * CERN-OHL-W v2.
  */
 
 /* CYCLE_HALF_WAIT should take into account the setup time of the slave
@@ -45,7 +45,7 @@ module spi_master #(
 reg miso_hot = 0;
 reg read_miso = 0;
 
-always @ (posedge clk) if (ENABLE_MISO) begin
+always @ (posedge clk) if (ENABLE_MISO == 1) begin
 	read_miso <= miso_hot;
 	miso_hot <= miso;
 end
@@ -70,20 +70,20 @@ task idle_state();
 	end else begin
 		sck <= 1;
 	end
-	if (ENABLE_MOSI) mosi <= 0;
+	if (ENABLE_MOSI == 1) mosi <= 0;
 	timer <= 0;
 	bit_counter <= 0;
 endtask
 
 task read_data();
-	if (ENABLE_MISO) begin
+	if (ENABLE_MISO == 1) begin
 		from_slave <= from_slave << 1;
 		from_slave[0] <= read_miso;
 	end
 endtask
 
 task write_data();
-	if (ENABLE_MOSI) begin
+	if (ENABLE_MOSI == 1) begin
 		mosi <= send_buf[WID-1];
 		send_buf <= send_buf << 1;
 	end
@@ -97,13 +97,13 @@ task setup_bits();
 	 * For mode 01 and mode 10, the first action is a WRITE.
 	 */
 	if (POLARITY == PHASE) begin
-		if (ENABLE_MOSI) begin
+		if (ENABLE_MOSI == 1) begin
 			mosi <= to_slave[WID-1];
 			send_buf <= to_slave << 1;
 		end
 		state <= CYCLE_WAIT;
 	end else begin
-		if (ENABLE_MISO) begin
+		if (ENABLE_MISO == 1) begin
 			send_buf <= to_slave;
 		end
 		state <= ON_CYCLE;
@@ -128,8 +128,8 @@ always @ (posedge clk) begin
 		finished <= 0;
 		state <= WAIT_ON_ARM;
 		ready_to_arm <= 1;
-		if (ENABLE_MISO) from_slave <= 0;
-		if (ENABLE_MOSI) send_buf <= 0;
+		if (ENABLE_MISO == 1) from_slave <= 0;
+		if (ENABLE_MOSI == 1) send_buf <= 0;
 	end else case (state)
 	WAIT_ON_ARM: begin
 `ifdef SIMULATION
diff --git a/spi_master_ss_template.v b/spi_master_ss.v
similarity index 91%
rename from spi_master_ss_template.v
rename to spi_master_ss.v
index e5624ce..f71a874 100644
--- a/spi_master_ss_template.v
+++ b/spi_master_ss.v
@@ -1,7 +1,7 @@
 /* (c) Peter McGoron 2022 v0.4
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v.2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * This code is disjunctively dual-licensed under the MPL v2.0, or the
+ * CERN-OHL-W v2.
  */
 
 /* spi master with integrated ability to wait a certain amount of cycles
diff --git a/spi_slave.v b/spi_slave.v
index 3530b5e..be1371f 100644
--- a/spi_slave.v
+++ b/spi_slave.v
@@ -1,7 +1,7 @@
 /* (c) Peter McGoron 2022 v0.4
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v.2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * This code is disjunctively dual-licensed under the MPL v2.0, or the
+ * CERN-OHL-W v2.
  */
 
 module spi_slave #(
@@ -32,7 +32,7 @@ module spi_slave #(
 reg mosi_hot = 0;
 reg read_mosi = 0;
 
-always @ (posedge clk) if (ENABLE_MOSI) begin
+always @ (posedge clk) if (ENABLE_MOSI == 1) begin
 	read_mosi <= mosi_hot;
 	mosi_hot <= mosi;
 end
@@ -48,21 +48,21 @@ reg [WID-1:0] send_buf = 0;
 `endif
 
 task read_data();
-	if (ENABLE_MOSI) begin
+	if (ENABLE_MOSI == 1) begin
 		from_master <= from_master << 1;
 		from_master[0] <= read_mosi;
 	end
 endtask
 
 task write_data();
-	if (ENABLE_MISO) begin
+	if (ENABLE_MISO == 1) begin
 		send_buf <= send_buf << 1;
 		miso <= send_buf[WID-1];
 	end
 endtask
 
 task setup_bits();
-	if (ENABLE_MISO) begin
+	if (ENABLE_MISO == 1) begin
 		/* at Mode 00, the transmission starts with
 		 * a rising edge, and at mode 11, it starts with a falling
 		 * edge. For both modes, these are READs.
@@ -93,9 +93,9 @@ always @ (posedge clk) begin
 		ss_delay <= 0;
 		ready_at_start <= 0;
 
-		if (ENABLE_MOSI) from_master <= 0;
+		if (ENABLE_MOSI == 1) from_master <= 0;
 
-		if (ENABLE_MISO) begin
+		if (ENABLE_MISO == 1) begin
 			miso <= 0;
 			send_buf <= 0;
 		end
diff --git a/tests/clean.sh b/tests/clean.sh
index 9d50089..238fbaf 100755
--- a/tests/clean.sh
+++ b/tests/clean.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
 
-rm -rf simtop_*
+rm -rf test_master* test_ss*
diff --git a/tests/mk.sh b/tests/mk.sh
deleted file mode 100755
index 707b753..0000000
--- a/tests/mk.sh
+++ /dev/null
@@ -1,85 +0,0 @@
-#!/bin/sh
-
-run_test() {
-	POL=$1
-	PHASE=$2
-	MASTER_TYPE=$3
-	SLAVE_TYPE=$4
-	DIR=$5
-	WID=$6
-	MODS=$7
-	EXTARG=$8
-	WIDLEN=$(printf "import math\nprint(math.floor(math.log2($WID) + 1))" | python3 -)
-
-	echo "running $POL$PHASE $MASTER_TYPE"
-
-	verilator --cc --exe -I.. -Wall -Wno-unused --trace --trace-fst \
-		--top-module simtop \
-		-GPOLARITY=$POL -GPHASE=$PHASE -GWID=$WID -CFLAGS -DWID=$WID \
-		-GWID_LEN=$WIDLEN \
-		-DSPI_MASTER_TYPE=$MASTER_TYPE -DSPI_SLAVE_TYPE=$SLAVE_TYPE \
-		-DVCDFILE="\"$DIR.fst\"" \
-		-DSIMULATION \
-		--Mdir $DIR \
-		$EXTARG \
-		simtop.v write_read.cpp $MODS \
-	|| exit 1
-
-	cd "$DIR"
-	make -f Vsimtop.mk
-	./Vsimtop
-}
-
-for POL in 0 1; do
-	for PHASE in 0 1; do
-		( \
-			run_test $POL $PHASE \
-			spi_master spi_slave \
-			simtop_$POL$PHASE 24 \
-			"../spi_master.v ../spi_slave.v"
-		) || exit 1
-
-		( \
-			run_test $POL $PHASE \
-			spi_master_ss spi_slave \
-			simtop_ss$POL$PHASE 24 \
-			"../spi_master_ss.v ../spi_slave.v" \
-			"-DSPI_MASTER_SS -CFLAGS -DSPI_MASTER_SS"
-		) || exit 1
-
-		( \
-			run_test $POL $PHASE \
-			spi_master_no_write spi_slave_no_read \
-			simtop_no_write_$POL$PHASE 24 \
-			"../spi_master_no_write.v ../spi_slave_no_read.v" \
-			"-DSPI_MASTER_NO_WRITE -CFLAGS -DSPI_MASTER_NO_WRITE"
-		) || exit 1
-
-		( \
-			run_test $POL $PHASE \
-			spi_master_ss_no_write spi_slave_no_read \
-			simtop_ss_no_write_$POL$PHASE 24 \
-			"../spi_master_ss_no_write.v ../spi_slave_no_read.v" \
-			"-DSPI_MASTER_NO_WRITE -CFLAGS -DSPI_MASTER_NO_WRITE
-			 -DSPI_MASTER_SS -CFLAGS -DSPI_MASTER_SS"
-		) || exit 1
-
-		( \
-			run_test $POL $PHASE \
-			spi_master_no_read spi_slave_no_write \
-			simtop_no_read_$POL$PHASE 24 \
-			"../spi_master_no_read.v ../spi_slave_no_write.v" \
-			"-DSPI_MASTER_NO_READ -CFLAGS -DSPI_MASTER_NO_READ"
-		) || exit 1
-
-		( \
-			run_test $POL $PHASE \
-			spi_master_ss_no_read spi_slave_no_write \
-			simtop_ss_no_read_$POL$PHASE 24 \
-			"../spi_master_ss_no_read.v ../spi_slave_no_write.v" \
-			"-DSPI_MASTER_NO_READ -CFLAGS -DSPI_MASTER_NO_READ
-			 -DSPI_MASTER_SS -CFLAGS -DSPI_MASTER_SS"
-		) || exit 1
-
-	done
-done
diff --git a/tests/runtests.py b/tests/runtests.py
new file mode 100755
index 0000000..5b883bb
--- /dev/null
+++ b/tests/runtests.py
@@ -0,0 +1,72 @@
+#!/usr/bin/python3
+
+import math
+import subprocess
+import sys
+import os
+from collections import namedtuple
+
+class Case:
+    def __init__(self, master_name, defflags, params):
+        self.master_name = master_name
+        self.defflags = defflags
+        self.params = params
+
+    def run(self, dirname, pol, phase, wid):
+        dirname = f'{dirname}{pol}{phase}'
+        widlen = math.floor(math.log2(wid) + 1)
+        args = ["verilator", "--cc", "--exe", "-I..", "-Wall", "--trace",
+                "--trace-fst", "-Wno-unused",
+                "--top-module", "simtop",
+                f"-GPOLARITY={pol}", f"-GPHASE={phase}",
+                f"-GWID={wid}", f"-CFLAGS", f"-DWID={wid}",
+                f"-GWID_LEN={widlen}",
+                f"-DSPI_MASTER_TYPE={self.master_name}",
+                f'-DVCDFILE="{dirname}/trace.fst"',
+                f"-DSIMULATION", 
+                f"--Mdir", dirname
+                ]
+
+        for flag in self.defflags:
+            args.extend([f'-D{flag}', '-CFLAGS', f'-D{flag}'])
+        for param in self.params:
+            args.append(f'-G{param}={self.params[param]}')
+
+        args.extend(['simtop.v', 'write_read.cpp', '../spi_slave.v', f'../{self.master_name}.v'])
+
+        print(args)
+        proc = subprocess.run(args, stdout=sys.stdout, stderr=sys.stderr)
+        if proc.returncode != 0:
+            print("Verilator failed")
+            return False
+
+        os.chdir(dirname)
+        proc = subprocess.run(["make", "-f", "Vsimtop.mk"], stdout=sys.stdout, stderr=sys.stderr)
+        if proc.returncode != 0:
+            print("Make failed")
+            os.chdir("..")
+            return False
+
+        proc = subprocess.run("./Vsimtop", stdout=sys.stdout, stderr=sys.stderr)
+        os.chdir("..")
+        if proc.returncode != 0:
+            print("Vsimtop failed")
+            return False
+        return True
+
+cases = {}
+# Add basic cases
+cases[f'test_master'] = Case("spi_master", [], {})
+cases[f'test_ss'] = Case("spi_master_ss", ["SPI_MASTER_SS"], {})
+cases[f'test_master_no_write'] = Case("spi_master", ['SPI_MASTER_NO_WRITE'], {'ENABLE_MOSI': 0})
+cases[f'test_ss_no_write'] = Case("spi_master_ss", ["SPI_MASTER_SS", 'SPI_MASTER_NO_WRITE'], {'ENABLE_MOSI': 0})
+cases[f'test_master_no_read'] = Case("spi_master", ['SPI_MASTER_NO_READ'], {'ENABLE_MISO': 1})
+cases[f'test_ss_no_read'] = Case("spi_master_ss", ["SPI_MASTER_SS", 'SPI_MASTER_NO_READ'], {'ENABLE_MISO': 1})
+
+failures=0
+for polarity in [0, 1]:
+    for phase in [0, 1]:
+        for casename in cases:
+            if not cases[casename].run(casename, polarity, phase, 24):
+                failures += 1
+print(f'Failures: {failures}')
diff --git a/tests/simtop.v b/tests/simtop.v
index 1e6662a..c280633 100644
--- a/tests/simtop.v
+++ b/tests/simtop.v
@@ -1,11 +1,13 @@
-/* (c) Peter McGoron 2022
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v.2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+/* (c) Peter McGoron 2022-2024 v0.4
+ *
+ * This code is disjunctively dual-licensed under the MPL v2.0, or the
+ * CERN-OHL-W v2.
  */
 
 module simtop
 #(
+	parameter ENABLE_MOSI = 1,
+	parameter ENABLE_MISO = 1,
 	parameter POLARITY = 0,
 	parameter PHASE = 0,
 	parameter WID = 24,
@@ -13,14 +15,13 @@ module simtop
 ) (
 	input clk,
 	input rst_L,
-`ifndef SPI_MASTER_NO_WRITE
+
 	input [WID-1:0] master_to_slave,
 	output [WID-1:0] from_master,
-`endif
-`ifndef SPI_MASTER_NO_READ
+
 	input [WID-1:0] slave_to_master,
 	output [WID-1:0] from_slave,
-`endif
+
 	input activate,
 `ifndef SPI_MASTER_SS
 	input ss,
@@ -31,13 +32,9 @@ module simtop
 	output err
 );
 
-`ifndef SPI_MASTER_NO_READ
 wire miso;
-`endif
 
-`ifndef SPI_MASTER_NO_WRITE
 wire mosi;
-`endif
 
 wire sck;
 wire ss_L;
@@ -46,8 +43,8 @@ wire ss_L;
 assign ss_L = !ss;
 `endif
 
-reg slave_finished;
-reg slave_error;
+wire slave_finished;
+wire slave_error;
 
 `SPI_MASTER_TYPE
 #(
@@ -55,6 +52,8 @@ reg slave_error;
 	.SS_WAIT(5),
 	.SS_WAIT_TIMER_LEN(3),
 `endif
+	.ENABLE_MOSI(ENABLE_MOSI),
+	.ENABLE_MISO(ENABLE_MISO),
 	.CYCLE_HALF_WAIT(5),
 	.TIMER_LEN(3),
 	.POLARITY(POLARITY),
@@ -64,14 +63,10 @@ reg slave_error;
 ) master (
 	.clk(clk),
 	.rst_L(rst_L),
-`ifndef SPI_MASTER_NO_WRITE
 	.to_slave(master_to_slave),
 	.mosi(mosi),
-`endif
-`ifndef SPI_MASTER_NO_READ
 	.from_slave(from_slave),
 	.miso(miso),
-`endif
 `ifdef SPI_MASTER_SS
 	.ss_L(ss_L),
 `endif
@@ -81,7 +76,9 @@ reg slave_error;
 	.arm(activate)
 );
 
-`SPI_SLAVE_TYPE #(
+spi_slave #(
+	.ENABLE_MOSI(ENABLE_MOSI),
+	.ENABLE_MISO(ENABLE_MISO),
 	.POLARITY(POLARITY),
 	.PHASE(PHASE),
 	.WID(WID),
@@ -91,14 +88,10 @@ reg slave_error;
 	.rst_L(rst_L),
 	.sck(sck),
 	.ss_L(ss_L),
-`ifndef SPI_MASTER_NO_WRITE
 	.from_master(from_master),
 	.mosi(mosi),
-`endif
-`ifndef SPI_MASTER_NO_READ
 	.to_master(slave_to_master),
 	.miso(miso),
-`endif
 	.finished(slave_finished),
 	.rdy(rdy),
 	.err(err)