Make Regex class serializable on JVM

#KT-16447 Fixed

Refactor helper functions for serialization tests.

libraries/stdlib/test/text/RegexJVMTest.kt

@@ -1,8 +1,27 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * 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.
+ */
+
 @file:kotlin.jvm.JvmVersion
 package test.text
 
 import kotlin.test.*
 import org.junit.Test
+import test.collections.compare
+import test.io.*
+import java.util.regex.Pattern
 
 
 class RegexJVMTest {
@@ -27,4 +46,28 @@ class RegexJVMTest {
         assertEquals("b", m2.groups[2]?.value)
         assertEquals(4..4, m2.groups[2]?.range)
     }
+
+
+    private fun compareRegex(expected: Regex, actual: Regex) = compare(expected, actual) {
+        propertyEquals(Regex::pattern)
+        propertyEquals(Regex::options)
+        propertyEquals("flags") { toPattern().flags() }
+    }
+
+    private fun equivalentAfterDeserialization(regex: Regex) = compareRegex(regex, serializeAndDeserialize(regex))
+
+    @Test fun serializeDeserializeRegex() {
+        equivalentAfterDeserialization(Regex(""))
+        equivalentAfterDeserialization(Regex("\\w+"))
+        equivalentAfterDeserialization(Regex("\\w+", RegexOption.IGNORE_CASE))
+        equivalentAfterDeserialization(Regex("\\w+", setOf(RegexOption.LITERAL, RegexOption.MULTILINE)))
+        equivalentAfterDeserialization(Pattern.compile("\\w+", Pattern.UNICODE_CASE).toRegex())
+    }
+
+    @Test fun deserializeRegexFromHex() {
+        val expected = Regex("\\w+", RegexOption.IGNORE_CASE)
+        // println(serializeToHex(expected))
+        val deserialized = deserializeFromHex<Regex>("ac ed 00 05 73 72 00 1c 6b 6f 74 6c 69 6e 2e 74 65 78 74 2e 52 65 67 65 78 24 53 65 72 69 61 6c 69 7a 65 64 00 00 00 00 00 00 00 00 02 00 02 49 00 05 66 6c 61 67 73 4c 00 07 70 61 74 74 65 72 6e 74 00 12 4c 6a 61 76 61 2f 6c 61 6e 67 2f 53 74 72 69 6e 67 3b 78 70 00 00 00 42 74 00 03 5c 77 2b")
+        compareRegex(expected, deserialized)
+    }
 }