Add a basic test of pgo clone

Issue: [ch7719]

Author: cbandy

testing/pgo_cli/cluster_clone_test.go

@@ -0,0 +1,75 @@
+package pgo_cli_test
+
+/*
+ Copyright 2020 Crunchy Data Solutions, Inc.
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestClusterClone(t *testing.T) {
+	t.Parallel()
+
+	requireStanzaExists := func(t *testing.T, namespace, cluster string, timeout time.Duration) {
+		t.Helper()
+
+		ready := func() bool {
+			output, err := pgo("show", "backup", cluster, "-n", namespace).Exec(t)
+			require.NoError(t, err)
+			return strings.Contains(output, "status: ok")
+		}
+
+		if !ready() {
+			requireWaitFor(t, ready, timeout, time.Second,
+				"timeout waiting for stanza of %q in %q", cluster, namespace)
+		}
+	}
+
+	withNamespace(t, func(namespace func() string) {
+		withCluster(t, namespace, func(cluster func() string) {
+			t.Run("clone", func(t *testing.T) {
+				t.Run("creates a copy of a cluster", func(t *testing.T) {
+					requireClusterReady(t, namespace(), cluster(), time.Minute)
+					requireStanzaExists(t, namespace(), cluster(), 2*time.Minute)
+
+					// data in the origin cluster followed by a WAL flush
+					_, stderr := clusterPSQL(t, namespace(), cluster(), `
+						CREATE TABLE original (data) AS VALUES ('one'), ('two');
+						DO $$ BEGIN IF current_setting('server_version_num')::int > 100000
+							THEN PERFORM pg_switch_wal();
+							ELSE PERFORM pg_switch_xlog();
+						END IF; END $$`)
+					require.Empty(t, stderr)
+
+					output, err := pgo("clone", cluster(), "rex", "-n", namespace()).Exec(t)
+					require.NoError(t, err)
+					require.NotEmpty(t, output)
+
+					defer teardownCluster(t, namespace(), "rex", time.Now())
+					requireClusterReady(t, namespace(), "rex", 3*time.Minute)
+
+					stdout, stderr := clusterPSQL(t, namespace(), cluster(), `TABLE original`)
+					require.Empty(t, stderr)
+					require.Contains(t, stdout, "(2 rows)",
+						"expected original data to be present in the clone")
+				})
+			})
+		})
+	})
+}