main.gopackage mainimport (    "net/http")func SomeFeature(host, a string) {    if a == "foo" {        resp, err := http.Get(host + "/foo")    }    if a == "bar" {        resp, err := http.Get(host + "/baz"))    }    // baz is missing, the test should error!}main_test.gopackage mainimport (    "net/http"    "net/http/httptest"    "testing")func TestSomeFeature(t *testing.T) {    server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {        w.WriteHeader(200)    }))    testCases := []struct {        name     string        variable string    }{        {            name:     "test 1",            variable: "foo",        },        {            name:     "test 2",            variable: "bar",        },        {            name:     "test 3",            variable: "baz",        },    }    for _, tc := range testCases {        tc := tc        t.Run(tc.name, func(t *testing.T) {            t.Parallel()            SomeFeature(server.URL, tc.variable)            // assert that the http call happened somehow?        })    }}去游樂場：https ://go.dev/play/p/EFanSSzgnbk如何斷言每個測試用例都向模擬服務(wù)器發(fā)送請求？如何斷言未發(fā)送請求？同時保持測試并行/并發(fā)？