Add unit tests for Case Insensitive Contains workarounds

core-java-modules/core-java-string-operations-2/src/test/java/com/baeldung/contains/CaseInsensitiveWorkaroundsUnitTest.java

@@ -0,0 +1,53 @@
+package com.baeldung.contains;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.regex.Pattern;
+
+/**
+ * BAEL-3739: Different ways to solve the contains() case insensitive behavior.
+ */
+public class CaseInsensitiveWorkaroundsUnitTest {
+
+    private String src = "Lorem ipsum dolor sit amet";
+    private String dest = "lorem";
+
+    @Test
+    public void givenString_whenCallingContainsWithToLowerOrUpperCase_shouldReturnTrue() {
+        // Use toLowerCase to avoid case insensitive issues
+        Assert.assertTrue(src.toLowerCase().contains(dest.toLowerCase()));
+
+        // Use toUpperCase to avoid case insensitive issues
+        Assert.assertTrue(src.toUpperCase().contains(dest.toUpperCase()));
+    }
+    
+    @Test
+    public void givenString_whenCallingStringMatches_shouldReturnTrue() {
+        // Use String Matches to avoid case insensitive issues
+        Assert.assertTrue(src.matches("(?i).*" + dest + ".*"));
+    }
+    
+    @Test
+    public void givenString_whenCallingStringRegionMatches_shouldReturnTrue() {
+        // Use String Region Matches to avoid case insensitive issues
+        CaseInsensitiveWorkarounds comparator = new CaseInsensitiveWorkarounds();
+        Assert.assertTrue(comparator.processRegionMatches(src, dest));
+    }
+    
+    
+    @Test
+    public void givenString_whenCallingPaternCompileMatcherFind_shouldReturnTrue() {
+        // Use Pattern Compile Matcher and Find to avoid case insensitive issues
+        Assert.assertTrue(Pattern.compile(Pattern.quote(dest), 
+            Pattern.CASE_INSENSITIVE) .matcher(src) .find());
+    }
+    
+    @Test
+    public void givenString_whenCallingStringUtilsContainsIgnoreCase_shouldReturnTrue() {
+        // Use StringUtils containsIgnoreCase to avoid case insensitive issues
+        Assert.assertTrue(StringUtils.containsIgnoreCase(src, dest));
+    }
+
+}