Config: Refactor version packages (#1887)

* Config: Move config versions to separate pacakges

* Config: Move version tests to blackbox texts

* Config: Protect registerVersion from overflow

* Config: Protect against version already registered

config/versions/v3/v3_test.go

@@ -0,0 +1,43 @@
+package v3_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	v3 "github.com/thrasher-corp/gocryptotrader/config/versions/v3"
+)
+
+func TestUpgradeExchange(t *testing.T) {
+	t.Parallel()
+
+	got, err := (&v3.Version{}).UpgradeExchange(context.Background(), nil)
+	require.NoError(t, err)
+	require.Nil(t, got)
+
+	payload := []byte(`{"orderbook": {"verificationBypass": false,"websocketBufferLimit": 5,"websocketBufferEnabled": false,"publishPeriod": 10000000000}}`)
+	expected := []byte(`{"orderbook": {"verificationBypass": false,"websocketBufferLimit": 5,"websocketBufferEnabled": false}}`)
+	got, err = (&v3.Version{}).UpgradeExchange(context.Background(), payload)
+	require.NoError(t, err)
+	require.Equal(t, expected, got)
+}
+
+func TestDowngradeExchange(t *testing.T) {
+	t.Parallel()
+
+	got, err := (&v3.Version{}).DowngradeExchange(context.Background(), nil)
+	require.NoError(t, err)
+	require.Nil(t, got)
+
+	payload := []byte(`{"orderbook": {"verificationBypass": false,"websocketBufferLimit": 5,"websocketBufferEnabled": false}}`)
+	expected := []byte(`{"orderbook": {"verificationBypass": false,"websocketBufferLimit": 5,"websocketBufferEnabled": false,"publishPeriod":10000000000}}`)
+	got, err = (&v3.Version{}).DowngradeExchange(context.Background(), payload)
+	require.NoError(t, err)
+	require.Equal(t, expected, got)
+}
+
+func TestExchanges(t *testing.T) {
+	t.Parallel()
+	assert := require.New(t)
+	assert.Equal([]string{"*"}, (&v3.Version{}).Exchanges())
+}