Clean up temp files more thoroughly after testing. (#7815)

Our test cases spew a lot of files and directories around $TMPDIR.  Make more
thorough use of the testing package's TempDir methods to ensure these are
cleaned up.

In a few cases, this required plumbing test contexts through existing helper
code. In a couple places an explicit path was required, to work around cases
where we do global setup during a TestMain function. Those cases probably
deserve more thorough cleansing (preferably with fire), but for now I have just
worked around it to keep focused on the cleanup.

config/toml.go

@@ -504,13 +504,13 @@ namespace = "{{ .Instrumentation.Namespace }}"
 
 /****** these are for test settings ***********/
 
-func ResetTestRoot(testName string) (*Config, error) {
-	return ResetTestRootWithChainID(testName, "")
+func ResetTestRoot(dir, testName string) (*Config, error) {
+	return ResetTestRootWithChainID(dir, testName, "")
 }
 
-func ResetTestRootWithChainID(testName string, chainID string) (*Config, error) {
+func ResetTestRootWithChainID(dir, testName string, chainID string) (*Config, error) {
 	// create a unique, concurrency-safe test directory under os.TempDir()
-	rootDir, err := os.MkdirTemp("", fmt.Sprintf("%s-%s_", chainID, testName))
+	rootDir, err := os.MkdirTemp(dir, fmt.Sprintf("%s-%s_", chainID, testName))
 	if err != nil {
 		return nil, err
 	}

config/toml_test.go

@@ -20,9 +20,7 @@ func ensureFiles(t *testing.T, rootDir string, files ...string) {
 
 func TestEnsureRoot(t *testing.T) {
 	// setup temp dir for test
-	tmpDir, err := os.MkdirTemp("", "config-test")
-	require.NoError(t, err)
-	defer os.RemoveAll(tmpDir)
+	tmpDir := t.TempDir()
 
 	// create root dir
 	EnsureRoot(tmpDir)
@@ -42,7 +40,7 @@ func TestEnsureTestRoot(t *testing.T) {
 	testName := "ensureTestRoot"
 
 	// create root dir
-	cfg, err := ResetTestRoot(testName)
+	cfg, err := ResetTestRoot(t.TempDir(), testName)
 	require.NoError(t, err)
 	defer os.RemoveAll(cfg.RootDir)
 	rootDir := cfg.RootDir