supply more tests and heading boilerplate

Signed-off-by: Hang Yin <[email protected]>

Author: delavet

pkg/epp/requestcontrol/director_test.go

@@ -85,7 +85,7 @@ func TestHandleRequest(t *testing.T) {
 		wantRespBody map[string]interface{}
 	}{
 		{
-			name: "successful request",
+			name: "successful completions request",
 			reqBodyMap: map[string]interface{}{
 				"model":  tsModel,
 				"prompt": "test prompt",
@@ -129,7 +129,42 @@ func TestHandleRequest(t *testing.T) {
 			},
 		},
 		{
-			name: "successful request with target model",
+			name: "successful chat completions request with multiple messages",
+			reqBodyMap: map[string]interface{}{
+				"model": tsModel,
+				"messages": []interface{}{
+					map[string]interface{}{
+						"role":    "developer",
+						"content": "You are a helpful assistant.",
+					},
+					map[string]interface{}{
+						"role":    "user",
+						"content": "Hello!",
+					},
+				},
+			},
+			wantReqCtx: &handlers.RequestContext{
+				Model:               tsModel,
+				ResolvedTargetModel: tsModel,
+				TargetPod:           "/pod1",
+				TargetEndpoint:      "address-1:8000",
+			},
+			wantRespBody: map[string]interface{}{
+				"model": tsModel,
+				"messages": []interface{}{
+					map[string]interface{}{
+						"role":    "developer",
+						"content": "You are a helpful assistant.",
+					},
+					map[string]interface{}{
+						"role":    "user",
+						"content": "Hello!",
+					},
+				},
+			},
+		},
+		{
+			name: "successful completions request with target model",
 			reqBodyMap: map[string]interface{}{
 				"model":  modelWithTarget,
 				"prompt": "test prompt",
@@ -149,6 +184,21 @@ func TestHandleRequest(t *testing.T) {
 			name:        "no model defined, expect err",
 			wantErrCode: errutil.BadRequest,
 		},
+		{
+			name: "prompt or messages not found, expect err",
+			reqBodyMap: map[string]interface{}{
+				"model": tsModel,
+			},
+			wantErrCode: errutil.BadRequest,
+		},
+		{
+			name: "empty messages, expect err",
+			reqBodyMap: map[string]interface{}{
+				"model":    tsModel,
+				"messages": []interface{}{},
+			},
+			wantErrCode: errutil.BadRequest,
+		},
 		{
 			name: "invalid model defined, expect err",
 			reqBodyMap: map[string]interface{}{

pkg/epp/util/request/body.go

@@ -1,3 +1,19 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
 package request
 
 import (
@@ -7,8 +23,7 @@ import (
 )
 
 func ExtractPromptFromRequestBody(body map[string]interface{}) (string, error) {
-	_, ok := body["messages"]
-	if ok {
+	if _, ok := body["messages"]; ok {
 		return extractPromptFromMessagesField(body)
 	}
 	return extractPromptField(body)
@@ -35,32 +50,33 @@ func extractPromptFromMessagesField(body map[string]interface{}) (string, error)
 	if !ok {
 		return "", errutil.Error{Code: errutil.BadRequest, Msg: "messages is not a list"}
 	}
+	if len(messageList) == 0 {
+		return "", errutil.Error{Code: errutil.BadRequest, Msg: "messages is empty"}
+	}
 
 	prompt := ""
-	if len(messageList) > 0 {
-		for _, msg := range messageList {
-			msgMap, ok := msg.(map[string]interface{})
-			if !ok {
-				continue
-			}
-			content, ok := msgMap["content"]
-			if !ok {
-				continue
-			}
-			contentStr, ok := content.(string)
-			if !ok {
-				continue
-			}
-			role, ok := msgMap["role"]
-			if !ok {
-				continue
-			}
-			roleStr, ok := role.(string)
-			if !ok {
-				continue
-			}
-			prompt += constructChatMessage(roleStr, contentStr)
+	for _, msg := range messageList {
+		msgMap, ok := msg.(map[string]interface{})
+		if !ok {
+			continue
+		}
+		content, ok := msgMap["content"]
+		if !ok {
+			continue
+		}
+		contentStr, ok := content.(string)
+		if !ok {
+			continue
+		}
+		role, ok := msgMap["role"]
+		if !ok {
+			continue
+		}
+		roleStr, ok := role.(string)
+		if !ok {
+			continue
 		}
+		prompt += constructChatMessage(roleStr, contentStr)
 	}
 	return prompt, nil
 }

pkg/epp/util/request/body_test.go

@@ -91,7 +91,7 @@ func TestExtractPromptFromRequestBody(t *testing.T) {
 	}
 }
 
-func TestExtractPromptForCompletions(t *testing.T) {
+func TestExtractPromptField(t *testing.T) {
 	tests := []struct {
 		name    string
 		body    map[string]interface{}