From e8351525c884714948d231b2d86f8fb9d46a4513 Mon Sep 17 00:00:00 2001
From: Vikas Ramsingh Rajput <vikas.rajput@crownconsult.com>
Date: Thu, 9 Jan 2020 23:22:47 +0300
Subject: [PATCH] BAEL-3655: Article Find vs Matches in Java Regex API - done

---
 .../RegexMatcherFindVsMatchesTest.java        | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 core-java-modules/core-java-text/src/test/java/com/baeldung/regex/matcher/RegexMatcherFindVsMatchesTest.java

diff --git a/core-java-modules/core-java-text/src/test/java/com/baeldung/regex/matcher/RegexMatcherFindVsMatchesTest.java b/core-java-modules/core-java-text/src/test/java/com/baeldung/regex/matcher/RegexMatcherFindVsMatchesTest.java
new file mode 100644
index 0000000000..95a2a39209
--- /dev/null
+++ b/core-java-modules/core-java-text/src/test/java/com/baeldung/regex/matcher/RegexMatcherFindVsMatchesTest.java
@@ -0,0 +1,63 @@
+package com.baeldung.regex.matcher;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.junit.jupiter.api.Test;
+
+public class RegexMatcherFindVsMatchesTest {
+
+    @Test
+    public void whenFindFourDigitWorks_thenCorrect() {
+        Pattern stringPattern = Pattern.compile("\\d\\d\\d\\d");
+        Matcher m = stringPattern.matcher("goodbye 2019 and welcome 2020");
+
+        assertTrue(m.find());
+        assertEquals(8, m.start());
+        assertEquals("2019", m.group());
+        assertEquals(12, m.end());
+
+        assertTrue(m.find());
+        assertEquals(25, m.start());
+        assertEquals("2020", m.group());
+        assertEquals(29, m.end());
+
+        assertFalse(m.find());
+    }
+
+    @Test
+    public void givenStartIndex_whenFindFourDigitWorks_thenCorrect() {
+        Pattern stringPattern = Pattern.compile("\\d\\d\\d\\d");
+        Matcher m = stringPattern.matcher("goodbye 2019 and welcome 2020");
+
+        assertTrue(m.find(20));
+        assertEquals(25, m.start());
+        assertEquals("2020", m.group());
+        assertEquals(29, m.end());
+    }
+
+    @Test
+    public void whenMatchFourDigitWorks_thenFail() {
+        Pattern stringPattern = Pattern.compile("\\d\\d\\d\\d");
+        Matcher m = stringPattern.matcher("goodbye 2019 and welcome 2020");
+        assertFalse(m.matches());
+    }
+
+    @Test
+    public void whenMatchFourDigitWorks_thenCorrect() {
+        Pattern stringPattern = Pattern.compile("\\d\\d\\d\\d");
+        Matcher m = stringPattern.matcher("2019");
+
+        assertTrue(m.matches());
+        assertEquals(0, m.start());
+        assertEquals("2019", m.group());
+        assertEquals(4, m.end());
+
+        assertTrue(m.matches());// matches will always return the same return
+    }
+
+}