add unit test for create command

cmd/create_command.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"io"
 	"os"
 	"strings"
 	"time"
@@ -22,7 +23,7 @@ const (
 	JSON
 )
 
-func RunCreateShiftPlan(arguments []string) error {
+func RunCreateShiftPlan(writer io.Writer, arguments []string) error {
 	enums := map[string]Format{"CVS": CVS, "Table": Table, "json": JSON}
 	exporters := map[Format]func() apis.Exporter{
 		Table: func() apis.Exporter {
@@ -55,12 +56,12 @@ func RunCreateShiftPlan(arguments []string) error {
 	createCommand.StringVar(primaryRules, "primary-rules", "vacation", "Rule to decide which employee should be on-call for the next shift")
 	createCommand.StringVar(secondaryRules, "secondary-rules", "vacation", "Rule to decide which employee should be on-call for the next shift")
 	createCommand.Usage = func() {
-		fmt.Fprintf(os.Stdout, "Create on-call schedule\n")
-		fmt.Fprintf(os.Stdout, "\nUsage\n")
-		fmt.Fprintf(os.Stdout, "  %s create [flags]\n", os.Args[0])
-		fmt.Fprintf(os.Stdout, "\nFlags:\n")
+		fmt.Fprintf(writer, "Create on-call schedule\n")
+		fmt.Fprintf(writer, "\nUsage\n")
+		fmt.Fprintf(writer, "  %s create [flags]\n", os.Args[0])
+		fmt.Fprintf(writer, "\nFlags:\n")
 		flag.PrintDefaults()
-		fmt.Fprintf(os.Stdout, "\nUse \"%s create -h\" for more information about a command\n", os.Args[0])
+		fmt.Fprintf(writer, "\nUse \"%s create -h\" for more information about a command\n", os.Args[0])
 	}
 
 	if err := createCommand.Parse(arguments); err != nil {
@@ -101,7 +102,7 @@ func RunCreateShiftPlan(arguments []string) error {
 		return fmt.Errorf("can not create on-call schedule: %w", err)
 	}
 
-	if err := exporters[outputFormat]().Write(plan, os.Stdout); err != nil {
+	if err := exporters[outputFormat]().Write(plan, writer); err != nil {
 		return fmt.Errorf("unexpecting error: %w", err)
 	}
 

cmd/create_command_test.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestRunCreateShiftPlan(t *testing.T) {
+	dir := t.TempDir()
+	tempFilePath := filepath.Join(dir, "team.json")
+	content := `{"employees": [{"id": "joe@example.com", "name": "Joe"}, {"id": "jan@example.com", "name": "Jan"}]}`
+	if err := os.WriteFile(tempFilePath, []byte(content), 0o600); err != nil {
+		t.FailNow()
+	}
+
+	type args struct {
+		arguments []string
+	}
+	tests := []struct {
+		name       string
+		args       args
+		wantWriter string
+		wantErrMsg string
+	}{
+		{
+			name:       "Print Usage when required flags are missing",
+			wantWriter: "Usage",
+			wantErrMsg: "missing required flag: start,end,team-file",
+		},
+		{
+			name: "Print Usage when use help flag",
+			args: args{
+				arguments: []string{
+					"-h",
+				},
+			},
+			wantWriter: "Usage",
+			wantErrMsg: "",
+		},
+		{
+			name: "Print an on-call schedule in JSON format",
+			args: args{
+				arguments: []string{
+					"--start", "2024-01-01 00:00:00",
+					"--end", "2024-01-08 00:00:00",
+					"--team-file", tempFilePath,
+					"--output", "json",
+				},
+			},
+			wantWriter: `[{"start":"2024-01-01T00:00:00Z","end":"2024-01-08T00:00:00Z","primary":"joe@example.com","secondary":"jan@example.com"}]`,
+			wantErrMsg: "",
+		},
+		{
+			name: "Print an error if shift plan cannot be created if rules are too restricted",
+			args: args{
+				arguments: []string{
+					"--start", "2024-01-01 00:00:00",
+					"--end", "2024-01-15 00:00:00",
+					"--team-file", tempFilePath,
+					"--primary-rules", "minimumfourshiftgap",
+					"--output", "json",
+				},
+			},
+			wantWriter: "",
+			wantErrMsg: "can not create on-call schedule: could not find available duty between 2024-01-08 00:00:00 +0000 UTC and 2024-01-15 00:00:00 +0000 UTC",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			writer := &bytes.Buffer{}
+			err := RunCreateShiftPlan(writer, tt.args.arguments)
+			if (err != nil) && tt.wantErrMsg != err.Error() {
+				t.Errorf("RunCreateShiftPlan() error = %v, wantErr %v", err, tt.wantErrMsg)
+				return
+			}
+			if gotWriter := writer.String(); !strings.Contains(gotWriter, tt.wantWriter) {
+				t.Errorf("RunCreateShiftPlan() gotWriter = %v, want %v", gotWriter, tt.wantWriter)
+			}
+		})
+	}
+}

cmd/main.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"os"
 	"slices"
 )
@@ -13,7 +14,7 @@ var ErrCommandNotFound = errors.New("command not found")
 type command struct {
 	name        string
 	description string
-	run         func([]string) error
+	run         func(io.Writer, []string) error
 }
 
 func main() {
@@ -67,7 +68,7 @@ func runCommand(cmd string, commands []command) error {
 		return fmt.Errorf("%w: %s", ErrCommandNotFound, cmd)
 	}
 
-	if err := commands[cmdIdx].run(os.Args[2:]); err != nil {
+	if err := commands[cmdIdx].run(os.Stdout, os.Args[2:]); err != nil {
 		return fmt.Errorf("\n\n%w", err)
 	}