I have a use case that needs to set cwd and env. It would be nice to be able to merge table into what is running. I have a workaround for some of the options. I just override the ones that this plugin adds after setup but it doesn't work for test.

This is what I am doing to fix some of my problems.

dap.configurations.go = {
				{
					type = "go",
					name = "(Arguments)",
					request = "launch",
					program = "${workspaceFolder}",
					cwd = "${workspaceFolder}",
					args = get_arguments,
					env = { LOG_COLOR = "0", },
				},
}

@friesencr I created a #77 to add an option for extra configuration arguments specifically for when calling debug_test().

For all other configurations, I've been just adding arguments manually by looping through the default provided configs after setup.

I'd also like to see this implemented. debug_test is an incredible convenience feature, but it's useless if your project has any kind of complex setup.

For example, I'm working on a repo that requires the --with-config flag to be set for testing and running locally. Since I can't pass that argument into any of the provided configs except (Arguments), I'm stuck manually passing in runtime regexes, and I can't take advantage of the really nice current test detection.

Another potential approach would be to have debug_test modify a predefined config that users can override. That way the function signature stays the same, and we can customize to our heart's content.
e.g.

-- WARNING: UNTESTED
-- get the basic config, which may have been overridden by the user
local function get_base_config(configName)
  local dap = load_module("dap")
  for _, v in ipairs(dap.configurations.go) do
    if v.name == configName then
      return v
    end
  end
end

local function debug_test(testname, testpath, build_flags)
  local dap = load_module("dap")
  local baseConfig = get_base_config("Debug test")
  local config = vim.tbl_deep_extend("force", {}, baseConfig, {
    -- merge user defined config with default args/build flags, and add the testname/path
    name = testname,
    program = testpath,
    args = vim.tbl_deep_extend("force", {}, baseConfig.args, { "-test.run", "^" .. testname .. "$" }),
    buildFlags = vim.tbl_deep_extend("force", {}, baseConfig.build_flags, build_flags or {}),
  })
  dap.run(config)
end

I'd also like to see this added. I'm working on a project with the oci8 SQL driver which requires the PKG_CONFIG_PATH environment variable to be set. I'm able to debug the whole project using a custom config, but I'd like to be able to use "Debug Test" for this as well.

It would be very helpful if someone provided a minimal Go project setup as a PR in the tests folder to reproduce this scenario with a failing debug test.