Add currency pair support

currency/pair/pair.go

@@ -0,0 +1,63 @@
+package pair
+
+import "strings"
+
+type CurrencyItem string
+
+func (c CurrencyItem) Lower() CurrencyItem {
+	return CurrencyItem(strings.ToLower(string(c)))
+}
+
+func (c CurrencyItem) Upper() CurrencyItem {
+	return CurrencyItem(strings.ToUpper(string(c)))
+}
+
+func (c CurrencyItem) String() string {
+	return string(c)
+}
+
+type CurrencyPair struct {
+	Delimiter      string       `json:"delimiter"`
+	FirstCurrency  CurrencyItem `json:"first_currency"`
+	SecondCurrency CurrencyItem `json:"second_currency"`
+}
+
+func (c CurrencyPair) GetFirstCurrency() CurrencyItem {
+	return c.FirstCurrency
+}
+
+func (c CurrencyPair) GetSecondCurrency() CurrencyItem {
+	return c.SecondCurrency
+}
+
+func (c CurrencyPair) Pair() CurrencyItem {
+	return c.FirstCurrency + CurrencyItem(c.Delimiter) + c.SecondCurrency
+}
+
+func NewCurrencyPairDelimiter(currency, delimiter string) CurrencyPair {
+	result := strings.Split(currency, delimiter)
+	return CurrencyPair{
+		Delimiter:      delimiter,
+		FirstCurrency:  CurrencyItem(result[0]),
+		SecondCurrency: CurrencyItem(result[1]),
+	}
+}
+
+func NewCurrencyPair(firstCurrency, secondCurrency string) CurrencyPair {
+	return CurrencyPair{
+		FirstCurrency:  CurrencyItem(firstCurrency),
+		SecondCurrency: CurrencyItem(secondCurrency),
+	}
+}
+
+func NewCurrencyPairFromString(currency string) CurrencyPair {
+	delmiters := []string{"_", "-"}
+	var delimiter string
+	for _, x := range delmiters {
+		if strings.Contains(currency, x) {
+			delimiter = x
+			return NewCurrencyPairDelimiter(currency, delimiter)
+		}
+	}
+	return NewCurrencyPair(currency[0:3], currency[3:])
+}

currency/pair/pair_test.go

@@ -0,0 +1,113 @@
+package pair
+
+import (
+	"testing"
+)
+
+func TestLower(t *testing.T) {
+	t.Parallel()
+	pair := CurrencyItem("BTCUSD")
+	actual := pair.Lower()
+	expected := CurrencyItem("btcusd")
+	if actual != expected {
+		t.Errorf("Test failed. Lower(): %s was not equal to expected value: %s",
+			actual, expected)
+	}
+}
+
+func TestUpper(t *testing.T) {
+	t.Parallel()
+	pair := CurrencyItem("btcusd")
+	actual := pair.Upper()
+	expected := CurrencyItem("BTCUSD")
+	if actual != expected {
+		t.Errorf("Test failed. Upper(): %s was not equal to expected value: %s",
+			actual, expected)
+	}
+}
+
+func TestString(t *testing.T) {
+	t.Parallel()
+	pair := NewCurrencyPair("BTC", "USD")
+	actual := "BTCUSD"
+	expected := pair.Pair().String()
+	if actual != expected {
+		t.Errorf("Test failed. String(): %s was not equal to expected value: %s",
+			actual, expected)
+	}
+}
+
+func TestGetFirstCurrency(t *testing.T) {
+	t.Parallel()
+	pair := NewCurrencyPair("BTC", "USD")
+	actual := pair.GetFirstCurrency()
+	expected := CurrencyItem("BTC")
+	if actual != expected {
+		t.Errorf("Test failed. GetFirstCurrency(): %s was not equal to expected value: %s", actual, expected)
+	}
+}
+
+func TestGetSecondCurrency(t *testing.T) {
+	t.Parallel()
+	pair := NewCurrencyPair("BTC", "USD")
+	actual := pair.GetSecondCurrency()
+	expected := CurrencyItem("USD")
+	if actual != expected {
+		t.Errorf("Test failed. GetSecondCurrency(): %s was not equal to expected value: %s", actual, expected)
+	}
+}
+
+func TestPair(t *testing.T) {
+	t.Parallel()
+	pair := NewCurrencyPair("BTC", "USD")
+	actual := pair.Pair()
+	expected := CurrencyItem("BTCUSD")
+	if actual != expected {
+		t.Errorf("Test failed. Pair(): %s was not equal to expected value: %s", actual, expected)
+	}
+}
+
+func TestNewCurrencyPair(t *testing.T) {
+	t.Parallel()
+	pair := NewCurrencyPair("BTC", "USD")
+	actual := pair.Pair()
+	expected := CurrencyItem("BTCUSD")
+	if actual != expected {
+		t.Errorf("Test failed. Pair(): %s was not equal to expected value: %s", actual, expected)
+	}
+}
+
+func TestNewCurrencyPairDelimiter(t *testing.T) {
+	t.Parallel()
+	pair := NewCurrencyPairDelimiter("BTC-USD", "-")
+	actual := pair.Pair()
+	expected := CurrencyItem("BTC-USD")
+	if actual != expected {
+		t.Errorf("Test failed. Pair(): %s was not equal to expected value: %s", actual, expected)
+	}
+
+	actual = CurrencyItem(pair.Delimiter)
+	expected = "-"
+	if actual != expected {
+		t.Errorf("Test failed. Delmiter: %s was not equal to expected value: %s", actual, expected)
+	}
+}
+
+func TestNewCurrencyPairFromString(t *testing.T) {
+	t.Parallel()
+	pairStr := "BTC-USD"
+	pair := NewCurrencyPairFromString(pairStr)
+	actual := pair.Pair()
+	expected := CurrencyItem("BTC-USD")
+	if actual != expected {
+		t.Errorf("Test failed. Pair(): %s was not equal to expected value: %s", actual, expected)
+	}
+
+	pairStr = "BTCUSD"
+	pair = NewCurrencyPairFromString(pairStr)
+	actual = pair.Pair()
+	expected = CurrencyItem("BTCUSD")
+	if actual != expected {
+		t.Errorf("Test failed. Pair(): %s was not equal to expected value: %s", actual, expected)
+	}
+}