Breakpoints not working (with pytest-cov)

[jeanlucthumm]

I set a breakpoint in my test file and it seems to pop up in the DAP logs:

[ DEBUG ] 2022-12-11T12:13:01Z-0800 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:1450 ]    "request"   {
  arguments = {
    breakpoints = { {
        line = 8
      } },
    lines = { 8 },
    source = {
      name = "waiter_test.py",
      path = "/home/jeanluc/Code/waiter_test.py"
    },
    sourceModified = false
  },
  command = "setBreakpoints",
  seq = 3,
  type = "request"
}
[ DEBUG ] 2022-12-11T12:13:01Z-0800 ] ...nvim/site/pack/packer/start/nvim-dap/lua/dap/session.lua:915 ] {
  body = {
    breakpoints = { {
        id = 0,
        line = 8,
        source = {
          name = "waiter_test.py",
          path = "/home/jeanluc/Code/waiter_test.py"
        },
        verified = true
      } }
  },
  command = "setBreakpoints",
  request_seq = 3,
  seq = 6,
  success = true,
  type = "response"
}

But when I launch via the test_method() function, the program runs but never breaks.

I looked at #17 and tried to change my python version. At first I was using /usr/bin/python (Python 3.10.8) since my global install had debugpy. Then I created custom virtual env with Python 3.9.2 but the problem persists.

My setup for the plugin:

    use {
        'mfussenegger/nvim-dap-python',
        requires = {'mfussenegger/nvim-dap'},
        config = function()
            require'dap-python'.setup('~/.virtualenv/debug/bin/python')
            require'dap-python'.test_runner = 'pytest'
        end
    }

[jeanlucthumm]

The debugger works when I'm inside a non-test, main() function, set a breakpoint, and do lua require'dap'.continue(), so maybe there's something wrong with pytest setups specifically?

[philkoch]

I'm having a similar issue. Configured nvim-dap-python with examples from the docs

local mason_path = vim.fn.glob(vim.fn.stdpath "data" .. "/mason/")
require("dap-python").setup(mason_path .. "packages/debugpy/venv/bin/python")
require("dap-python").test_runner = "pytest"
-- mappings
lvim.builtin.which_key.mappings["dm"] = { "<cmd>lua require('dap-python').test_method()<cr>", "Test Method" }
lvim.builtin.which_key.mappings["df"] = { "<cmd>lua require('dap-python').test_class()<cr>", "Test Class" }

When invoking the test_method-action in a pytest-unittest file, the debugger starts as expected, but does not stop at breakpoints. Same as for the others, the debugger and breakpoints work fine when used in "normal" python modules.

[mfussenegger]

A minimal example with reproduction steps would be good.

Using a simple:

def inc(x):
    return x + 1

def test_answer():
    assert inc(3) == 5

And running :lua require('dap-python').test_method() with the cursor in test_answer, test_runner set to pytest, and a breakpoint in the inc body works fine for me.

[philkoch]

Sorry for the late reply, I didn't find time to test it earlier. I found out what broke it for me. I'm using a poetry environment in which all dev-tools are configured via the pyproject.toml. PyTest is also configured in there:

[tool.pytest.ini_options]
addopts = "--cov" # <-- no stopping at breakpoints with --cov
testpaths = ["tests"]

When the --cov is added nvim-dap-python does not stop at breakpoints, when I remove it it works fine.

[mfussenegger]

Looks like this is a pytest-cov / debugpy limitation. See https://github.com/microsoft/debugpy/issues/863#issuecomment-1059040881