refactor cmd interface for better testing

This change allows for E2E blackbox testing of pomodoro commands
by adding a New(*pomo.Config) *Cli.cmd function to the cmd module.
In a subsequent PR we should refactor pomo.Config into a public
module.

pkg/cmd/cmd.go

@@ -232,15 +232,17 @@ func _config(config *pomo.Config) func(*cli.Cmd) {
 	}
 }
 
-func Run() {
+func New(config *pomo.Config) *cli.Cli {
 	app := cli.App("pomo", "Pomodoro CLI")
 	app.LongDesc = "Pomo helps you track what you did, how long it took you to do it, and how much effort you expect it to take."
 	app.Spec = "[OPTIONS]"
 	var (
-		config = &pomo.Config{}
 		path = app.StringOpt("p path", defaultConfigPath(), "path to the pomo config directory")
 	)
 	app.Before = func() {
+		if config == nil {
+			config = &pomo.Config{}
+		}
 		maybe(pomo.LoadConfig(*path, config))
 	}
 	app.Version("v version", pomo.Version)
@@ -252,5 +254,7 @@ func Run() {
 	app.Command("list l", "list historical tasks", list(config))
 	app.Command("delete d", "delete a stored task", _delete(config))
 	app.Command("status st", "output the current status", _status(config))
-	app.Run(os.Args)
+	return app
 }
+
+func Run() { New(nil).Run(os.Args) }

pkg/cmd/cmd_test.go

@@ -0,0 +1,50 @@
+package cmd
+
+import (
+	"database/sql"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	pomo "github.com/kevinschoon/pomo/pkg/internal"
+)
+
+func checkErr(t *testing.T, err error) {
+    if err != nil {
+        t.Helper()
+        t.Fatal(err)
+    }
+}
+
+func initTestConfig(t *testing.T) (*pomo.Store, *pomo.Config) {
+     tmpPath, err := ioutil.TempDir(os.TempDir(), "pomo-test")
+     checkErr(t, err)
+     config := &pomo.Config{
+        DateTimeFmt: "2006-01-02 15:04",
+        BasePath: tmpPath,
+        DBPath: filepath.Join(tmpPath, "pomo.db"),
+        SocketPath: filepath.Join(tmpPath, "pomo.sock"),
+        IconPath: filepath.Join(tmpPath, "icon.png"),
+     }
+     store, err := pomo.NewStore(config.DBPath)
+     checkErr(t, err)
+     checkErr(t, pomo.InitDB(store))
+     return store, config
+}
+
+func TestPomoCreate(t *testing.T) {
+    store, config := initTestConfig(t)
+    cmd := New(config)
+    checkErr(t, cmd.Run([]string{"pomo", "create", "fuu"}))
+    // verify the task was created
+    store.With(func(tx *sql.Tx) error {
+        task, err := store.ReadTask(tx, 1)
+        checkErr(t, err)
+        if task.Message != "fuu" {
+            checkErr(t, fmt.Errorf("task should have message fuu, got %s", task.Message))
+        }
+        return nil
+    })
+}