DigestUtil: add performance test.

GitOrigin-RevId: 72a2e9854041554ebb4f944323407614dedbea3a

java/java-tests/testSrc/com/intellij/util/indexing/DigestUtilTest.kt

@@ -0,0 +1,35 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.util.indexing
+
+import com.intellij.testFramework.PlatformTestUtil
+import com.intellij.util.io.DigestUtil
+import org.apache.commons.lang.RandomStringUtils
+import org.junit.Test
+import java.util.concurrent.Callable
+import java.util.concurrent.Executors
+
+class DigestUtilTest {
+
+  private val digest = DigestUtil.sha1()
+
+  @Test
+  fun `digest evaluation performance test`() {
+    val stringsNumber = 1000
+    val stringLength = 10000
+    val randomBytes = (0 until stringsNumber)
+      .map { RandomStringUtils.random(stringLength) }
+      .map { it.toByteArray() }
+
+    val threadPool = Executors.newFixedThreadPool(8)
+    val callableList = randomBytes.map { Callable { calculateContentHash(it) } }
+
+    PlatformTestUtil.startPerformanceTest("DigestUtil works quickly enough", 250) {
+      threadPool.invokeAll(callableList)
+    }.usesAllCPUCores().attempts(5).assertTiming()
+  }
+
+  private fun calculateContentHash(bytes: ByteArray) {
+    DigestUtil.calculateContentHash(digest, bytes)
+  }
+
+}