test: use FST waveform format by default

Also upgrade cocotb to 2.0.1 which fixes cocotb/cocotb#5025

Author: urish

.github/workflows/test.yaml

@@ -37,12 +37,12 @@ jobs:
           paths: "test/results.xml"
         if: always()
 
-      - name: upload vcd
+      - name: upload waveform and test results
         if: success() || failure()
         uses: actions/upload-artifact@v4
         with:
-          name: test-vcd
+          name: test-results
           path: |
-            test/tb.vcd
+            test/tb.fst
             test/results.xml
             test/output/*

.gitignore

@@ -1,6 +1,8 @@
 .DS_Store
 .idea
 *.vcd
+*.fst
+*.fst.hier
 runs
 tt_submission
 src/user_config.json

test/Makefile

@@ -3,7 +3,7 @@
 
 # defaults
 SIM ?= icarus
-WAVES ?= 1
+FST ?= -fst # Use more efficient FST format
 TOPLEVEL_LANG ?= verilog
 SRC_DIR = $(PWD)/../src
 PROJECT_SOURCES = project.v

test/README.md

@@ -24,14 +24,24 @@ Then run:
 make -B GATES=yes
 ```
 
-## How to view the VCD file
+If you wish to save the waveform in VCD format instead of FST format, edit tb.v to use `$dumpfile("tb.vcd");` and then run:
+
+```sh
+make -B FST=
+```
+
+This will generate `tb.vcd` instead of `tb.fst`.
+
+## How to view the waveform file
 
 Using GTKWave
+
 ```sh
-gtkwave tb.vcd tb.gtkw
+gtkwave tb.fst tb.gtkw
 ```
 
 Using Surfer
+
 ```sh
-surfer tb.vcd
+surfer tb.fst
 ```

test/requirements.txt

@@ -1,2 +1,2 @@
 pytest==8.4.2
-cocotb==2.0.0
+cocotb==2.0.1

test/tb.gtkw

@@ -2,7 +2,7 @@
 [*] GTKWave Analyzer v3.4.0 (w)1999-2022 BSI
 [*] Mon Nov 20 16:00:28 2023
 [*]
-[dumpfile] "/home/uri/p/tt-new-template-proto/test/tb.vcd"
+[dumpfile] "/home/uri/p/tt-new-template-proto/test/tb.fst"
 [dumpfile_mtime] "Mon Nov 20 15:58:34 2023"
 [dumpfile_size] 1110
 [savefile] "/home/uri/p/tt-new-template-proto/test/tb.gtkw"

test/tb.v

@@ -6,9 +6,9 @@
 */
 module tb ();
 
-  // Dump the signals to a VCD file. You can view it with gtkwave or surfer.
+  // Dump the signals to a FST file. You can view it with gtkwave or surfer.
   initial begin
-    $dumpfile("tb.vcd");
+    $dumpfile("tb.fst");
     $dumpvars(0, tb);
     #1;
   end