Return error if adding when runner hasn't been started

Before this used to block

main.go

@@ -48,6 +48,7 @@ func NewShellRunnerWithShell(shell string) *ShellRunner {
 		callbacks:  make(chan func(), MAX_RESULTS),
 		shell:      shell,
 		activeCmds: make(map[*exec.Cmd]struct{}),
+		isStopped:  true,
 	}
 }
 
@@ -75,16 +76,18 @@ func (sr *ShellRunner) Start() {
 			}
 		}
 	}()
+
+	sr.isStopped = false
 }
 
 // AddCommand adds a shell command to be executed with an optional callback.
-// No commands can be added if the runner has been stopped.
+// No commands can be added if the runner has been stopped or not yet started.
 func (sr *ShellRunner) AddCommand(command string, callback func(*CommandResult)) error {
 	sr.mu.Lock()
 	defer sr.mu.Unlock()
 
 	if sr.isStopped {
-		return errors.New("runner has been stopped, cannot add new commands")
+		return errors.New("runner is stopped, cannot add new commands")
 	}
 
 	sr.cmdQueue <- func() *CommandResult {

main_test.go

@@ -78,7 +78,7 @@ func TestShellRunnerCallback(t *testing.T) {
 
 	// Make sure stop and kill both exit gracefully after the runner is stopped
 	runner.Stop()
-	runner.Stop()
+	runner.Kill()
 }
 
 func TestShellRunnerKillWithTimeout(t *testing.T) {
@@ -122,3 +122,12 @@ func TestStopPreventsNewCommands(t *testing.T) {
 		t.Fatal("expected error when adding command after stop, but got none")
 	}
 }
+
+func TestAddingPriorToStart(t *testing.T) {
+	runner := tortoise.NewShellRunner()
+
+	err := runner.AddCommand("echo should not run", nil)
+	if err == nil {
+		t.Fatal("Should have failed to add prior to starting runner")
+	}
+}