fsm: initial import

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

fsm/fsm_test.go

@@ -0,0 +1,49 @@
+package fsm
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"testing"
+)
+
+func TestFSMStart(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	pfb := func(_ context.Context, state string, _ map[string]interface{}) {
+		fmt.Fprintf(buf, "before state %s\n", state)
+	}
+	pfa := func(_ context.Context, state string, _ map[string]interface{}) {
+		fmt.Fprintf(buf, "after state %s\n", state)
+	}
+	f := New(StateInitial("1"), StateHookBefore(pfb), StateHookAfter(pfa))
+	f1 := func(_ context.Context, args map[string]interface{}) (string, map[string]interface{}, error) {
+		if v, ok := args["request"].(string); !ok || v == "" {
+			return "", nil, fmt.Errorf("empty request")
+		}
+		return "2", map[string]interface{}{"response": "test2"}, nil
+	}
+	f2 := func(_ context.Context, args map[string]interface{}) (string, map[string]interface{}, error) {
+		if v, ok := args["response"].(string); !ok || v == "" {
+			return "", nil, fmt.Errorf("empty response")
+		}
+		return "", map[string]interface{}{"response": "test"}, nil
+	}
+	f.State("1", f1)
+	f.State("2", f2)
+	args, err := f.Start(ctx, map[string]interface{}{"request": "test1"})
+	if err != nil {
+		t.Fatal(err)
+	} else if v, ok := args["response"].(string); !ok || v == "" {
+		t.Fatalf("nil rsp: %#+v", args)
+	} else if v != "test" {
+		t.Fatalf("invalid rsp %#+v", args)
+	}
+
+	if !bytes.Contains(buf.Bytes(), []byte(`before state 1`)) ||
+		!bytes.Contains(buf.Bytes(), []byte(`before state 2`)) ||
+		!bytes.Contains(buf.Bytes(), []byte(`after state 1`)) ||
+		!bytes.Contains(buf.Bytes(), []byte(`after state 2`)) {
+		t.Fatalf("fsm not works properly or hooks error, buf: %s", buf.Bytes())
+	}
+}