feat: Add UI for awaiting agent connections (#578)

* feat: Add stage to build logs

This adds a stage property to logs, and refactors the job logs
cliui.

It also adds tests to the cliui for build logs!

* feat: Add stage to build logs

This adds a stage property to logs, and refactors the job logs
cliui.

It also adds tests to the cliui for build logs!

* feat: Add config-ssh and tests for resiliency

* Rename "Echo" test to "ImmediateExit"

* Fix Terraform resource agent association

* Fix logs post-cancel

* Fix select on Windows

* Remove terraform init logs

* Move timer into it's own loop

* Fix race condition in provisioner jobs

* Fix requested changes

cli/cliui/agent_test.go

@@ -0,0 +1,53 @@
+package cliui_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/atomic"
+
+	"github.com/coder/coder/cli/cliui"
+	"github.com/coder/coder/codersdk"
+	"github.com/coder/coder/pty/ptytest"
+)
+
+func TestAgent(t *testing.T) {
+	t.Parallel()
+	var disconnected atomic.Bool
+	ptty := ptytest.New(t)
+	cmd := &cobra.Command{
+		RunE: func(cmd *cobra.Command, args []string) error {
+			err := cliui.Agent(cmd, cliui.AgentOptions{
+				WorkspaceName: "example",
+				Fetch: func(ctx context.Context) (codersdk.WorkspaceResource, error) {
+					resource := codersdk.WorkspaceResource{
+						Agent: &codersdk.WorkspaceAgent{
+							Status: codersdk.WorkspaceAgentDisconnected,
+						},
+					}
+					if disconnected.Load() {
+						resource.Agent.Status = codersdk.WorkspaceAgentConnected
+					}
+					return resource, nil
+				},
+				FetchInterval: time.Millisecond,
+				WarnInterval:  10 * time.Millisecond,
+			})
+			return err
+		},
+	}
+	cmd.SetOutput(ptty.Output())
+	cmd.SetIn(ptty.Input())
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		err := cmd.Execute()
+		require.NoError(t, err)
+	}()
+	ptty.ExpectMatch("lost connection")
+	disconnected.Store(true)
+	<-done
+}