test: add tests for csv reader and writer

output_csv_test.go

@@ -0,0 +1,42 @@
+package script
+
+import (
+	"bytes"
+	"os"
+	"testing"
+)
+
+func TestCSVWriter(t *testing.T) {
+	path := "testdata/output_csv.csv"
+
+	os.Remove(path)
+	defer os.Remove(path)
+
+	w, err := newCSVwriter(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := []byte("one,two,three\none,two,three\n")
+
+	row := []string{"one", "two", "three"}
+
+	for range 2 {
+		if err := w.Write(row); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	if err := w.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	b, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("err reading output file: %s", err)
+	}
+
+	if !bytes.Equal(want, b) {
+		t.Errorf("incorrect result, want: %s, have: %s", string(want), string(b))
+	}
+}