Alerting: Modify configuration apply and save semantics - v2 (#34143)

* Save default configuration to the database and copy over secure settings

pkg/tests/api/alerting/testing.go

@@ -0,0 +1,82 @@
+package alerting
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const defaultAlertmanagerConfigJSON = `
+{
+	"template_files": null,
+	"alertmanager_config": {
+		"route": {
+			"receiver": "grafana-default-email"
+		},
+		"templates": null,
+		"receivers": [{
+			"name": "grafana-default-email",
+			"grafana_managed_receiver_configs": [{
+				"id": 0,
+				"uid": "",
+				"name": "email receiver",
+				"type": "email",
+				"isDefault": true,
+				"sendReminder": false,
+				"disableResolveMessage": false,
+				"frequency": "",
+				"created": "0001-01-01T00:00:00Z",
+				"updated": "0001-01-01T00:00:00Z",
+				"settings": {
+					"addresses": "\u003cexample@email.com\u003e"
+				},
+				"secureFields": {}
+			}]
+		}]
+	}
+}
+`
+
+func getRequest(t *testing.T, url string, expStatusCode int) *http.Response {
+	t.Helper()
+	// nolint:gosec
+	resp, err := http.Get(url)
+	t.Cleanup(func() {
+		require.NoError(t, resp.Body.Close())
+	})
+	require.NoError(t, err)
+	if expStatusCode != resp.StatusCode {
+		b, err := ioutil.ReadAll(resp.Body)
+		require.NoError(t, err)
+		t.Fatal(string(b))
+	}
+	return resp
+}
+
+func postRequest(t *testing.T, url string, body string, expStatusCode int) *http.Response {
+	t.Helper()
+	buf := bytes.NewReader([]byte(body))
+	// nolint:gosec
+	resp, err := http.Post(url, "application/json", buf)
+	t.Cleanup(func() {
+		require.NoError(t, resp.Body.Close())
+	})
+	require.NoError(t, err)
+	if expStatusCode != resp.StatusCode {
+		b, err := ioutil.ReadAll(resp.Body)
+		require.NoError(t, err)
+		t.Fatal(string(b))
+	}
+	return resp
+}
+
+func getBody(t *testing.T, body io.ReadCloser) string {
+	t.Helper()
+	b, err := ioutil.ReadAll(body)
+	require.NoError(t, err)
+	return string(b)
+}