Tests: Use currency.NewBTCUSD and NewBTCUSDT (#1895)

* Tests: Use currency.NewUSD and NewUSDT

Simple refactor to use the provided shortcut methods

* Github: Add CI check to ensure NewPair not used

Add a step to ensure NewPair(BTC, USD*) isn't used

exchanges/orderbook/calculator_test.go

@@ -12,7 +12,7 @@ import (
 func testSetup() Base {
 	return Base{
 		Exchange: "a",
-		Pair:     currency.NewPair(currency.BTC, currency.USD),
+		Pair:     currency.NewBTCUSD(),
 		Asks: []Tranche{
 			{Price: 7000, Amount: 1},
 			{Price: 7001, Amount: 2},

exchanges/orderbook/orderbook_test.go

@@ -31,7 +31,7 @@ func TestSubscribeToExchangeOrderbooks(t *testing.T) {
 	_, err := SubscribeToExchangeOrderbooks("")
 	assert.ErrorIs(t, err, ErrOrderbookNotFound)
 
-	p := currency.NewPair(currency.BTC, currency.USD)
+	p := currency.NewBTCUSD()
 
 	b := Base{
 		Pair:     p,
@@ -51,7 +51,7 @@ func TestVerify(t *testing.T) {
 	b := Base{
 		Exchange:        "TestExchange",
 		Asset:           asset.Spot,
-		Pair:            currency.NewPair(currency.BTC, currency.USD),
+		Pair:            currency.NewBTCUSD(),
 		VerifyOrderbook: true,
 	}
 

exchanges/orderbook/simulator/simulator_test.go

@@ -24,7 +24,7 @@ func TestSimulate(t *testing.T) {
 		},
 	}
 	o, err := b.UpdateOrderbook(t.Context(),
-		currency.NewPair(currency.BTC, currency.USD), asset.Spot)
+		currency.NewBTCUSD(), asset.Spot)
 	if err != nil {
 		t.Fatal(err)
 	}