Unable to produce dump.vcd file using run function with Verilator

[TamirBr-H]

Description

I am unable to generate the dump.vcd waveform file when using the run function from cocotb-test.

Steps for reproduce:

1. Environment setup
cocotb-test version: 0.2.5
Python version: 3.9.16
Verilator version: 5.030
cocotb version: 1.9.2
OS: CentOS 7
2. Run the following Python code:

from cocotb_test.simulator import run

run(
    verilog_sources=["path/to/your.sv"],  # Replace with your Verilog source file path
    simulator="verilator",
    toplevel="toplevel_module_name",      # Replace with your top-level module name
    module="test",                        # Replace with your test module name
    extra_args=["--trace", "--trace-structs"],
    plus_args=["--trace"],
    waves=True,
    force_compile=False
)

Expected Behavior: The dump.vcd file should be produced in the expected output location, containing the simulation waveforms.

Actual Behavior: The simulation runs without errors, but the dump.vcd file is not generated.

Additional Notes

• I also tried variations in the run configuration, such as moving "--trace-structs" from extra_args to plus_args, but the issue persists.
• This issue might be related to how Verilator interacts with cocotb-test, or there could be a missing configuration step.

[SuperChamp234]

did anyone get a fix to this? I'd love to see waves while using verilator...

[MrWater98]

I have same problem.

[Gbps]

Still an issue