1 files changed, 100 insertions, 0 deletions
diff --git a/okio/src/jvmTest/java/okio/MessageDigestConsistencyTest.kt b/okio/src/jvmTest/java/okio/MessageDigestConsistencyTest.kt
new file mode 100644
index 00000000..962d0119
--- /dev/null
+++ b/okio/src/jvmTest/java/okio/MessageDigestConsistencyTest.kt
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2020 Square, Inc.
+ *
+ * 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 okio
+
+import okio.ByteString.Companion.toByteString
+import okio.internal.HashFunction
+import okio.internal.Md5
+import okio.internal.Sha1
+import okio.internal.Sha256
+import okio.internal.Sha512
+import org.assertj.core.api.Assertions.assertThat
+import java.security.MessageDigest
+import java.util.Random
+import kotlin.test.Test
+
+/**
+ * Confirm Okio is consistent with the JDK's MessageDigest algorithms for various sizes and slices.
+ * This makes repeated calls to update() with byte arrays of various sizes and contents to defend
+ * against bugs in batching inputs.
+ */
+class MessageDigestConsistencyTest {
+  @Test fun sha1() {
+    test("SHA-1") { Sha1() }
+  }
+
+  @Test fun sha256() {
+    test("SHA-256") { Sha256() }
+  }
+
+  @Test fun sha512() {
+    test("SHA-512") { Sha512() }
+  }
+
+  @Test fun md5() {
+    test("MD5") { Md5() }
+  }
+
+  private fun test(algorithm: String, newHashFunction: () -> HashFunction) {
+    for (seed in 0L until 1000L) {
+      for (updateCount in 0 until 10) {
+        test(
+          algorithm = algorithm,
+          hashFunction = newHashFunction(),
+          seed = seed,
+          updateCount = updateCount
+        )
+      }
+    }
+  }
+
+  private fun test(
+    algorithm: String,
+    hashFunction: HashFunction,
+    seed: Long,
+    updateCount: Int
+  ) {
+    val data = Buffer()
+
+    val random = Random(seed)
+    for (i in 0 until updateCount) {
+      val size = random.nextInt(1000) + 1 // size must be >= 1.
+      val byteArray = ByteArray(size).also { random.nextBytes(it) }
+      val offset = random.nextInt(size)
+      val byteCount = random.nextInt(size - offset)
+
+      hashFunction.update(
+        input = byteArray,
+        offset = offset,
+        byteCount = byteCount
+      )
+
+      data.write(
+        source = byteArray,
+        offset = offset,
+        byteCount = byteCount
+      )
+    }
+
+    val okioHash = hashFunction.digest()
+
+    val byteArray = data.readByteArray()
+    val jdkMessageDigest = MessageDigest.getInstance(algorithm)
+    val jdkHash = jdkMessageDigest.digest(byteArray)
+
+    assertThat(okioHash.toByteString()).isEqualTo(jdkHash.toByteString())
+  }
+}