feat(cli): add local and UTC time options to ping cmd (#16648)

It's sometimes useful to see when each pong was received, for
correlating these times with other events.

---------

Signed-off-by: Danny Kopping <danny@coder.com>

cli/ping_test.go

@@ -69,4 +69,60 @@ func TestPing(t *testing.T) {
 		cancel()
 		<-cmdDone
 	})
+
+	t.Run("1PingWithTime", func(t *testing.T) {
+		t.Parallel()
+
+		tests := []struct {
+			name string
+			utc  bool
+		}{
+			{name: "LocalTime"},      // --time renders the pong response time.
+			{name: "UTC", utc: true}, // --utc implies --time, so we expect it to also contain the pong time.
+		}
+
+		for _, tc := range tests {
+			t.Run(tc.name, func(t *testing.T) {
+				t.Parallel()
+
+				client, workspace, agentToken := setupWorkspaceForAgent(t)
+				args := []string{"ping", "-n", "1", workspace.Name, "--time"}
+				if tc.utc {
+					args = append(args, "--utc")
+				}
+
+				inv, root := clitest.New(t, args...)
+				clitest.SetupConfig(t, client, root)
+				pty := ptytest.New(t)
+				inv.Stdin = pty.Input()
+				inv.Stderr = pty.Output()
+				inv.Stdout = pty.Output()
+
+				_ = agenttest.New(t, client.URL, agentToken)
+				_ = coderdtest.AwaitWorkspaceAgents(t, client, workspace.ID)
+
+				ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitLong)
+				defer cancel()
+
+				cmdDone := tGo(t, func() {
+					err := inv.WithContext(ctx).Run()
+					assert.NoError(t, err)
+				})
+
+				// RFC3339 is the format used to render the pong times.
+				rfc3339 := `\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?`
+
+				// Validate that dates are rendered as specified.
+				if tc.utc {
+					rfc3339 += `Z`
+				} else {
+					rfc3339 += `(?:Z|[+-]\d{2}:\d{2})`
+				}
+
+				pty.ExpectRegexMatch(`\[` + rfc3339 + `\] pong from ` + workspace.Name)
+				cancel()
+				<-cmdDone
+			})
+		}
+	})
 }