{noenv: "example.com", req: "http://foo.example.com/", env: "proxy", want: "<nil>"},
	{noenv: ".foo.com", req: "http://example.com/", env: "proxy", want: "http://proxy"},
}

func testProxyForRequest(t *testing.T, tt proxyFromEnvTest, proxyForRequest func(req *Request) (*url.URL, error)) {
	t.Helper()
	reqURL := tt.req
	if reqURL == "" {
		reqURL = "http://example.com"
	}