Running the test suite writes garbage to ~/.gitconfig

[tpickett66]

While working on PR #2599 I ran the test suite several times. Later, when I moved on to other work, I found myself unable to run terraform init due to git wanting a password to clone repositories. After looking through my git config I found the following new entries:

[url "https://user@hostname/"]
	insteadOf = ssh://git@hostname
[url "https://x-access-token/@github.com"]
	insteadOf = ssh://[email protected]
[url "https://x-access-token/@127.0.0.1:50571"]
	insteadOf = ssh://[email protected]:50571
[url "https://x-access-token/@some-host"]
	insteadOf = ssh://git@some-host
[url "https://x-access-token/@127.0.0.1:53454"]
	insteadOf = ssh://[email protected]:53454

Which traced back to Atlantis' test suite. Rather than overwriting developers config files the test suite should set some combination of GIT_CONFIG and GIT_CONFIG_GLOBAL to point git at a clean, temporary location.

[mrwacky42]

Looks like the culprit is the tests here: https://github.com/runatlantis/atlantis/blob/master/server/events/git_cred_writer_test.go#L128-L154

Based on git-config docs, how about something like this:

diff --git a/server/events/git_cred_writer_test.go b/server/events/git_cred_writer_test.go
index 9d9583ab..48533a5a 100644
--- a/server/events/git_cred_writer_test.go
+++ b/server/events/git_cred_writer_test.go
@@ -134,7 +134,9 @@ func TestWriteGitCreds_ConfigureGitCredentialHelper(t *testing.T) {
        Ok(t, err)

        expOutput := `store`
-       actOutput, err := exec.Command("git", "config", "--global", "credential.helper").Output()
+       cmd := exec.Command("git", "config", "--global", "credential.helper")
+       cmd.Env = append(os.Environ(), fmt.Sprintf("GIT_CONFIG_GLOBAL=%s", filepath.Join(tmp, "gitconfig")))
+       actOutput, err := cmd.Output()
        Ok(t, err)
        Equals(t, expOutput+"\n", string(actOutput))
 }

Well, running in Docker gets me this result, so .. Close but no cigar.

--- FAIL: TestWriteGitCreds_ErrIfCannotRead (0.04s)
    git_cred_writer_test.go:117: exp err to contain "open /tmp/2289098227/.git-credentials: permission denied" but err was nil

EDIT: Paying attention, I see this is a different test that's failing and the test also fails on unmodified code. I'll try again later, or make an actual PR.

[mrwacky42]

(And no, this is only part of the solution because this only reads from a new place, and WriteGitCreds() would need to be updated when testing.)