change azure engine config to modelMapper (#306)

* change azure engine config to azure modelMapper config

* Update go.mod

* Revert "Update go.mod"

This reverts commit 78d14c58f2a9ce668da43f6adbe20b60afcfe0d7.

* lint fix

* add test

* lint fix

* lint fix

* lint fix

* opt

* opt

* opt

* opt

config_test.go

@@ -0,0 +1,62 @@
+package openai_test
+
+import (
+	"testing"
+
+	. "github.com/sashabaranov/go-openai"
+)
+
+func TestGetAzureDeploymentByModel(t *testing.T) {
+	cases := []struct {
+		Model                string
+		AzureModelMapperFunc func(model string) string
+		Expect               string
+	}{
+		{
+			Model:  "gpt-3.5-turbo",
+			Expect: "gpt-35-turbo",
+		},
+		{
+			Model:  "gpt-3.5-turbo-0301",
+			Expect: "gpt-35-turbo-0301",
+		},
+		{
+			Model:  "text-embedding-ada-002",
+			Expect: "text-embedding-ada-002",
+		},
+		{
+			Model:  "",
+			Expect: "",
+		},
+		{
+			Model:  "models",
+			Expect: "models",
+		},
+		{
+			Model:  "gpt-3.5-turbo",
+			Expect: "my-gpt35",
+			AzureModelMapperFunc: func(model string) string {
+				modelmapper := map[string]string{
+					"gpt-3.5-turbo": "my-gpt35",
+				}
+				if val, ok := modelmapper[model]; ok {
+					return val
+				}
+				return model
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.Model, func(t *testing.T) {
+			conf := DefaultAzureConfig("", "https://test.openai.azure.com/")
+			if c.AzureModelMapperFunc != nil {
+				conf.AzureModelMapperFunc = c.AzureModelMapperFunc
+			}
+			actual := conf.GetAzureDeploymentByModel(c.Model)
+			if actual != c.Expect {
+				t.Errorf("Expected %s, got %s", c.Expect, actual)
+			}
+		})
+	}
+}