Update checkRunEnv to create nested tmp subdirectories

runner/_testdata/nested/.air.toml

@@ -0,0 +1 @@
+tmp_dir = "./tmp/nested"

runner/engine.go

@@ -104,7 +104,7 @@ func (e *Engine) checkRunEnv() error {
 	p := e.config.tmpPath()
 	if _, err := os.Stat(p); os.IsNotExist(err) {
 		e.runnerLog("mkdir %s", p)
-		if err := os.Mkdir(p, 0o755); err != nil {
+		if err := os.MkdirAll(p, 0o755); err != nil {
 			e.runnerLog("failed to mkdir, error: %s", err.Error())
 			return err
 		}

runner/engine_test.go

@@ -49,6 +49,23 @@ func TestCheckRunEnv(t *testing.T) {
 	}
 }
 
+func TestCheckRunEnvNestedTmp(t *testing.T) {
+	_ = os.Unsetenv(airWd)
+	engine, err := NewEngine("_testdata/nested/.air.toml", true)
+	if err != nil {
+		t.Fatalf("Should not be fail: %s.", err)
+	}
+
+	err = engine.checkRunEnv()
+	if err != nil {
+		t.Fatal("Should not return an err")
+	}
+
+	if _, err := os.Stat("./tmp/nested"); os.IsNotExist(err) {
+		t.Fatal("Should create a nested tmp folder")
+	}
+}
+
 func TestWatching(t *testing.T) {
 	engine, err := NewEngine("", true)
 	if err != nil {