Add tests for Checksum hex validation and HTTP error handling

Author: Tim te Beek

rewrite-core/src/test/java/org/openrewrite/ChecksumTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 org.openrewrite;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.ipc.http.HttpSender;
+
+import java.io.ByteArrayInputStream;
+import java.io.UncheckedIOException;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class ChecksumTest {
+
+    @Test
+    void fromHexWithValidInput() {
+        Checksum checksum = Checksum.fromHex("SHA-256", "abcdef01");
+        assertThat(checksum.getHexValue()).isEqualTo("abcdef01");
+    }
+
+    @Test
+    void fromHexRejectsNonHexInput() {
+        assertThatThrownBy(() -> Checksum.fromHex("SHA-256", "<?xml version"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("not valid hexadecimal");
+    }
+
+    @Test
+    void fromUriRejectsNonSuccessfulResponse() {
+        HttpSender httpSender = request -> new HttpSender.Response(
+                403,
+                new ByteArrayInputStream("<?xml version=\"1.0\"?>".getBytes(StandardCharsets.UTF_8)),
+                () -> {
+                });
+
+        assertThatThrownBy(() -> Checksum.fromUri(httpSender, URI.create("https://example.com/checksum.sha256")))
+                .isInstanceOf(UncheckedIOException.class)
+                .hasMessageContaining("403");
+    }
+
+    @Test
+    void fromUriTrimsWhitespace() {
+        HttpSender httpSender = request -> new HttpSender.Response(
+                200,
+                new ByteArrayInputStream("abcdef01\n".getBytes(StandardCharsets.UTF_8)),
+                () -> {
+                });
+
+        Checksum checksum = Checksum.fromUri(httpSender, URI.create("https://example.com/checksum.sha256"));
+        assertThat(checksum.getHexValue()).isEqualTo("abcdef01");
+    }
+}