feat: add chain writer

chain_test.go

@@ -0,0 +1,49 @@
+package script
+
+import (
+	"context"
+	"slices"
+	"testing"
+)
+
+func TestChainProcessor(t *testing.T) {
+	p := func(_ context.Context, in []string) ([]string, error) {
+		in[0] = in[0] + in[0]
+		return in, nil
+	}
+
+	chain := ChainProcessor(p, p, p)
+
+	in := []string{"a"}
+	want := []string{"aaaaaaaa"}
+
+	res, err := chain(t.Context(), in)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !slices.Equal(res, want) {
+		t.Fatalf("slices are not equal, have: %+v, want: %+v", res, want)
+	}
+}
+
+func TestChainWriter(t *testing.T) {
+	w1 := NewMemWriter()
+	w2 := NewMemWriter()
+
+	w := ChainWriter(w1, w2)
+
+	in := []string{"a"}
+
+	if err := w.Write(in); err != nil {
+		t.Fatal(err)
+	}
+
+	if !slices.Equal(w1.Output()[0], in) {
+		t.Fatalf("w1 slices are not equal, have: %+v, want: %+v", w1.Output()[0], in)
+	}
+
+	if !slices.Equal(w2.Output()[0], in) {
+		t.Fatalf("w2 slices are not equal, have: %+v, want: %+v", w2.Output()[0], in)
+	}
+}