Adds initial framework for tests in commands.go

This adds initial tests and a pattern to use as a framework for adding
unit tests for the rest of the `tea.Cmd` functions in `commands.go`, as well
as explanation of the pattern for future contributors.

The `tui.go` `Update()` command will receive `tea.Msg`s and return `tea.Cmd`s.
All the `tea.Cmds` (except those in the actual Bubble Tea framework) will
be collected in `commands.go`.  Each command will have an outgoing `tea.Msg`
that contains any relevant results. Commands may also have incoming
`tea.Msg`s, but these are deprecated as the `Update()` function is
converted to call commands directly rather than `func() tea.Msg {}`
commands, which are an unnecessary intermediary.

Signed-off-by: Chris Collins <collins.christopher@gmail.com>

Author: clcollins

pkg/pd/mock.go

@@ -0,0 +1,64 @@
+package pd
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/PagerDuty/go-pagerduty"
+)
+
+var ErrMockError = fmt.Errorf("pd.Mock(): mock error") // Used to mock errors in unit tests
+
+type MockPagerDutyClient struct {
+	PagerDutyClient
+}
+
+func (m *MockPagerDutyClient) GetTeamWithContext(ctx context.Context, team string) (*pagerduty.Team, error) {
+	return &pagerduty.Team{Name: team}, nil
+}
+
+func (m *MockPagerDutyClient) GetIncidentWithContext(ctx context.Context, id string) (*pagerduty.Incident, error) {
+	// Provided so we can mock error responses for unit tests
+	if id == "err" {
+		return &pagerduty.Incident{}, ErrMockError
+	}
+	return &pagerduty.Incident{
+		APIObject: pagerduty.APIObject{
+			ID: id, // Incidents will always come back with the same ID as the request
+		},
+	}, nil
+}
+
+func (m *MockPagerDutyClient) ListIncidentAlertsWithContext(ctx context.Context, id string, opts pagerduty.ListIncidentAlertsOptions) (*pagerduty.ListAlertsResponse, error) {
+	if id == "err" {
+		return &pagerduty.ListAlertsResponse{}, ErrMockError
+	}
+	return &pagerduty.ListAlertsResponse{
+		Alerts: []pagerduty.IncidentAlert{
+			{
+				APIObject: pagerduty.APIObject{
+					ID: "QABCDEFG1234567",
+				},
+			},
+			{
+				APIObject: pagerduty.APIObject{
+					ID: "QABCDEFG7654321",
+				},
+			},
+		},
+	}, nil
+}
+
+func (m *MockPagerDutyClient) ListIncidentNotesWithContext(ctx context.Context, id string) ([]pagerduty.IncidentNote, error) {
+	if id == "err" {
+		return []pagerduty.IncidentNote{}, ErrMockError
+	}
+	return []pagerduty.IncidentNote{
+		{
+			ID: "QABCDEFG1234567",
+		},
+		{
+			ID: "QABCDEFG7654321",
+		},
+	}, nil
+}

pkg/pd/pd_test.go

@@ -1,7 +1,6 @@
 package pd
 
 import (
-	"context"
 	"errors"
 	"reflect"
 	"testing"
@@ -10,14 +9,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-type MockPagerDutyClient struct {
-	PagerDutyClient
-}
-
-func (m *MockPagerDutyClient) GetTeamWithContext(ctx context.Context, team string) (*pagerduty.Team, error) {
-	return &pagerduty.Team{Name: team}, nil
-}
-
 func TestGetTeams(t *testing.T) {
 	t.Run("GetTeams", func(t *testing.T) {
 		mockClient := new(MockPagerDutyClient)

pkg/rand/rand.go

@@ -0,0 +1,29 @@
+package rand
+
+// Credit to https://www.calhoun.io/creating-random-strings-in-go/
+
+import (
+	"math/rand"
+	"time"
+)
+
+const charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+
+var seededRand *rand.Rand = rand.New(
+	rand.NewSource(time.Now().UnixNano()))
+
+func StringWithCharset(length int, charset string) string {
+	b := make([]byte, length)
+	for i := range b {
+		b[i] = charset[seededRand.Intn(len(charset))]
+	}
+	return string(b)
+}
+
+func String(length int) string {
+	return StringWithCharset(length, charset)
+}
+
+func ID(prefix string) string {
+	return prefix + String(13)
+}

pkg/tui/commands.go

@@ -18,31 +18,89 @@ import (
 	"github.com/clcollins/srepd/pkg/pd"
 )
 
+// This file contains the commands that are used in the Bubble Tea update function.
+// These commands are functions that return a tea.Cmd, which performs I/O with
+// another system, such as the PagerDuty API, the filesystem, or the user's terminal,
+// and shouldn't perform any actual processing themselves.
+//
+// The returned tea.Cmd is executed by the Bubble Tea runtime, and the result of the
+// command is sent back to the update function as a tea.Msg.
+//
+// See getIncident() as a good example of this pattern.
+
 const (
 	gettingUserStatus      = "getting user info..."
 	loadingIncidentsStatus = "loading incidents..."
 )
 
+// TODO: Deprecate incoming message
+// getIncidentMsg is a message that triggers the fetching of an incident
+type getIncidentMsg string
+
+// gotIncidentMsg is a message that contains the fetched incident
+type gotIncidentMsg struct {
+	incident *pagerduty.Incident
+	err      error
+}
+
+// getIncident returns a command that fetches the incident with the given ID
+// or returns a setStatusMsg with nilIncidentMsg if the provided ID is empty
+func getIncident(p *pd.Config, id string) tea.Cmd {
+	return func() tea.Msg {
+		if id == "" {
+			return setStatusMsg{nilIncidentMsg}
+		}
+		ctx := context.Background()
+		i, err := p.Client.GetIncidentWithContext(ctx, id)
+		return gotIncidentMsg{i, err}
+	}
+}
+
+// gotIncidentAlertsMsg is a message that contains the fetched incident alerts
+type gotIncidentAlertsMsg struct {
+	alerts []pagerduty.IncidentAlert
+	err    error
+}
+
+// getIncidentAlerts returns a command that fetches the alerts for the given incident
+func getIncidentAlerts(p *pd.Config, id string) tea.Cmd {
+	return func() tea.Msg {
+		if id == "" {
+			return setStatusMsg{nilIncidentMsg}
+		}
+		a, err := pd.GetAlerts(p.Client, id, pagerduty.ListIncidentAlertsOptions{})
+		return gotIncidentAlertsMsg{a, err}
+	}
+}
+
+// got IncidentNotesMsg is a message that contains the fetched incident notes
+type gotIncidentNotesMsg struct {
+	notes []pagerduty.IncidentNote
+	err   error
+}
+
+// getIncidentNotes returns a command that fetches the notes for the given incident
+func getIncidentNotes(p *pd.Config, id string) tea.Cmd {
+	return func() tea.Msg {
+		if id == "" {
+			return setStatusMsg{nilIncidentMsg}
+		}
+		n, err := pd.GetNotes(p.Client, id)
+		return gotIncidentNotesMsg{n, err}
+	}
+}
+
+// HOUSEKEEPING: The above are commands that have complete unit tests and incoming
+// and outgoing tea.Msg types, ordered alphabetically. Below are commands that need to
+// be refactored to have unit tests and incoming and outgoing tea.Msg types, ordered
+
 type errMsg struct{ error }
 type setStatusMsg struct{ string }
 type waitForSelectedIncidentThenDoMsg struct {
 	action tea.Cmd
 	msg    tea.Msg
 }
 
-//lint:ignore U1000 - future proofing
-type waitForSelectedIncidentThenRenderMsg string
-
-//lint:ignore U1000 - future proofing
-// func updateSelectedIncident(p *pd.Config, id string) tea.Msg {
-// This return won't work as is - these are not tea.Cmd functions
-// 	return tea.Sequence(
-// 		getIncident(p, id),
-// 		getIncidentAlerts(p, id),
-// 		getIncidentNotes(p, id),
-// 	)
-// }
-
 type TickMsg struct {
 	Tick int
 }
@@ -112,50 +170,6 @@ func renderIncident(m *model) tea.Cmd {
 	}
 }
 
-type getIncidentMsg string
-type gotIncidentMsg struct {
-	incident *pagerduty.Incident
-	err      error
-}
-
-func getIncident(p *pd.Config, id string) tea.Cmd {
-	if id == "" {
-		return func() tea.Msg {
-			return setStatusMsg{"No incident selected"}
-		}
-	}
-	return func() tea.Msg {
-		ctx := context.Background()
-		i, err := p.Client.GetIncidentWithContext(ctx, id)
-		return gotIncidentMsg{i, err}
-	}
-}
-
-type gotIncidentAlertsMsg struct {
-	alerts []pagerduty.IncidentAlert
-	err    error
-}
-
-func getIncidentAlerts(p *pd.Config, id string) tea.Cmd {
-	return func() tea.Msg {
-		a, err := pd.GetAlerts(p.Client, id, pagerduty.ListIncidentAlertsOptions{})
-		return gotIncidentAlertsMsg{a, err}
-	}
-}
-
-type gotIncidentNotesMsg struct {
-	notes []pagerduty.IncidentNote
-	err   error
-}
-
-// getIncidentNotes returns a command that fetches the notes for the given incident
-func getIncidentNotes(p *pd.Config, id string) tea.Cmd {
-	return func() tea.Msg {
-		n, err := pd.GetNotes(p.Client, id)
-		return gotIncidentNotesMsg{n, err}
-	}
-}
-
 // AssignedToAnyUsers returns true if the incident is assigned to any of the given users
 func AssignedToAnyUsers(i pagerduty.Incident, ids []string) bool {
 	for _, a := range i.Assignments {