feat(spec): Add HttpMethod enum

Author: thced

src/main/java/com/retailsvc/http/spec/HttpMethod.java

@@ -0,0 +1,19 @@
+package com.retailsvc.http.spec;
+
+import java.util.Locale;
+
+public enum HttpMethod {
+  GET,
+  POST,
+  PUT,
+  DELETE,
+  PATCH,
+  HEAD,
+  OPTIONS,
+  TRACE,
+  CONNECT;
+
+  public static HttpMethod parse(String s) {
+    return HttpMethod.valueOf(s.toUpperCase(Locale.ROOT));
+  }
+}

src/test/java/com/retailsvc/http/spec/HttpMethodTest.java

@@ -0,0 +1,28 @@
+package com.retailsvc.http.spec;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class HttpMethodTest {
+  @Test
+  void parsesUppercase() {
+    assertThat(HttpMethod.parse("GET")).isEqualTo(HttpMethod.GET);
+  }
+
+  @Test
+  void parsesLowercase() {
+    assertThat(HttpMethod.parse("get")).isEqualTo(HttpMethod.GET);
+  }
+
+  @Test
+  void parsesMixed() {
+    assertThat(HttpMethod.parse("PaTcH")).isEqualTo(HttpMethod.PATCH);
+  }
+
+  @Test
+  void unknownThrows() {
+    org.junit.jupiter.api.Assertions.assertThrows(
+        IllegalArgumentException.class, () -> HttpMethod.parse("foo"));
+  }
+}