Add USD currency to price format on Twitter

Signed-off-by: Julien Riou <julien@riou.xyz>

twitter.go

@@ -90,16 +90,18 @@ func (c *TwitterNotifier) buildHashtags(productName string) string {
 	return ""
 }
 
-// replace price currency by its symbol
+// formatPrice using internationalization rules
+// euro sign is placed after the value
+// default the currency, or symbol if applicable, is placed before the value
 func formatPrice(value float64, currency string) string {
-	var symbol string
 	switch {
 	case currency == "EUR":
-		symbol = "€"
+		return fmt.Sprintf("%.2f€", value)
+	case currency == "USD":
+		return fmt.Sprintf("$%.2f", value)
 	default:
-		symbol = currency
+		return fmt.Sprintf("%s%.2f", currency, value)
 	}
-	return fmt.Sprintf("%.2f%s", value, symbol)
 }
 
 // NotifyWhenAvailable create a Twitter status for announcing that a product is available

twitter_test.go

@@ -55,3 +55,27 @@ func TestBuildHashtags(t *testing.T) {
 		})
 	}
 }
+
+func TestFormatPrice(t *testing.T) {
+	tests := []struct {
+		value    float64
+		currency string
+		expected string
+	}{
+		{999.99, "EUR", "999.99€"},
+		{999.99, "USD", "$999.99"},
+		{999.99, "CHF", "CHF999.99"},
+		{999.99, "", "999.99"},
+	}
+
+	for i, tc := range tests {
+		t.Run(fmt.Sprintf("TestFormatPrice#%d", i), func(t *testing.T) {
+			got := formatPrice(tc.value, tc.currency)
+			if got != tc.expected {
+				t.Errorf("for value %0.2f and currency %s, got %s, want %s", tc.value, tc.currency, got, tc.expected)
+			} else {
+				t.Logf("for value %0.2f and currency %s, got %s, want %s", tc.value, tc.currency, got, tc.expected)
+			}
+		})
+	}
+}