Initialize safe defaults in HttpResponse no-arg constructorFix/httpresponse defaults

src/main/java/org/juv25d/http/HttpResponse.java

@@ -11,10 +11,10 @@ public class HttpResponse {
 
     private int statusCode;
     private String statusText;
-    private Map<String, String> headers;
+    private final Map<String, String> headers;
     private byte[] body;
 
-    public HttpResponse(){
+    public HttpResponse() {
         this.statusCode = 200;
         this.statusText = "OK";
         this.headers = new LinkedHashMap<>();
@@ -23,8 +23,8 @@ public HttpResponse(){
 
     public HttpResponse(int statusCode, String statusText, Map<String, String> headers, byte[] body) {
         this.statusCode = statusCode;
-        this.statusText = statusText;
-        this.headers = headers != null ? new LinkedHashMap<>(headers) : new LinkedHashMap<>();
+        this.statusText = Objects.requireNonNull(statusText, "statusText must not be null");
+        this.headers = new LinkedHashMap<>(headers != null ? headers : Map.of());
         this.body = body != null ? body.clone() : new byte[0];
     }
 

src/test/java/org/juv25d/http/HttpResponseTest.java

@@ -0,0 +1,25 @@
+package org.juv25d.http;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+
+class HttpResponseTest {
+
+    @Test
+    void defaultConstructor_hasSafeDefaults_andSetHeaderDoesNotThrow() {
+        HttpResponse response = new HttpResponse();
+
+        assertThat(response.statusCode()).isEqualTo(200);
+        assertThat(response.statusText()).isEqualTo("OK");
+        assertThat(response.headers()).isNotNull();
+        assertThat(response.body()).isNotNull();
+        assertThat(response.body()).isEmpty();
+
+        assertThatCode(() -> response.setHeader("Content-Type", "text/plain"))
+            .doesNotThrowAnyException();
+
+        assertThat(response.headers()).containsEntry("Content-Type", "text/plain");
+    }
+}