Learning about subtests in Golang with Parallel execution

main_test.go

// Sequential
// $ go test
// PASS
// ok	7.312s

// Parallel On
// $ go test
// PASS
// ok 0.985s

package tests

import (
	"fmt"
	"net/http"
	"testing"
)

// Config
var host string = "opendata.arcgis.com"

func TestTime(t *testing.T) {
	testCases := []struct {
		proto string
		resp  string
		path  string
	}{
		{"https", "204 OK", "/datasets"},
		{"https", "200 OK", "/sites"},
		{"https", "200 OK", "/api/v2/sites"},
		{"https", "200 OK", "/api"},
		{"https", "200 OK", "/sites"},
		{"https", "200 OK", "/utilities"},
		{"https", "202 Accepted", "/datasets/ddd4129848f54e1a92f7d4080284b27a_0/geohash"},
		{"https", "200 OK", "/torii-provider-arcgis/redirect.html"},
		{"https", "200 OK", "/datasets/#{dataset}"},
		{"https", "200 OK", "/datasets"},
		{"https", "200 OK", "/"},
		{"https", "200 OK", "/robots.txt"},
	}
	for _, tc := range testCases {
		tc := tc
		client := &http.Client{}

		t.Run(fmt.Sprintf("%s in %s", tc.path, tc.resp), func(st *testing.T) {
			st.Parallel()

			uri := tc.proto + "://" + host + tc.path
			req, err := http.NewRequest("GET", uri, nil)
			if err != nil {
				t.Fatalf("couldn't build request %s%s: error %s", uri, err)
			}

			resp, err := client.Do(req)
			if err != nil {
				t.Fatalf("couldn't request %s: error %s", uri, err)
			}
			defer resp.Body.Close()

			if got := resp.Status; got != tc.resp {
				t.Errorf("%s responded with %s; expected %s", uri, got, tc.resp)
			}
		})
	}
}