Add the functionality and the unit testing for LTrim and RTrim

core-java-modules/core-java-string-operations-2/src/test/java/com/baeldung/trim/LTrimRTrimUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.trim;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.regex.Pattern;
+
+/**
+ * BAEL-3755: LTrim and RTrim examples.
+ */
+public class LTrimRTrimUnitTest {
+
+    private String src = "        White spaces left and right            ";
+    private final static String ltrimResult = "White spaces left and right            ";
+    private final static String rtrimResult = "        White spaces left and right";
+
+    @Test
+    public void givenString_whenCallingWhileCharacters_thenReturnsTrue() {
+        String ltrim = LTrimRTrim.whileLtrim(src);
+        String rtrim = LTrimRTrim.whileRtrim(src);
+
+        // Compare the Strings obtained and the expected
+        Assert.assertTrue(ltrimResult.equalsIgnoreCase(ltrim));
+
+        Assert.assertTrue(rtrimResult.equalsIgnoreCase(rtrim));
+    }
+
+    @Test
+    public void givenString_whenCallingContainsWithReplaceAll_shouldReturnTrue() {
+        // Use replaceAll with Regular Expressions
+        String ltrim = src.replaceAll("^\\s+", "");
+        String rtrim = src.replaceAll("\\s+$", "");
+
+        // Compare the Strings obtained and the expected
+        Assert.assertTrue(ltrimResult.equalsIgnoreCase(ltrim));
+
+        Assert.assertTrue(rtrimResult.equalsIgnoreCase(rtrim));
+    }
+
+    @Test
+    public void givenString_whenCallingPaternCompileMatcherReplaceAll_thenReturnsTrue() {
+        // Use Pattern Compile Matcher and Find to avoid case insensitive issues
+        String ltrim = LTrimRTrim.patternLtrim(src);
+        String rtrim = LTrimRTrim.patternRtrim(src);
+
+        // Compare the Strings obtained and the expected
+        Assert.assertTrue(ltrimResult.equalsIgnoreCase(ltrim));
+
+        Assert.assertTrue(rtrimResult.equalsIgnoreCase(rtrim));
+    }
+
+    @Test
+    public void givenString_whenCallingGuavaCharMatcher_thenReturnsTrue() {
+        // Use StringUtils containsIgnoreCase to avoid case insensitive issues
+        String ltrim = LTrimRTrim.guavaLtrim(src);
+        String rtrim = LTrimRTrim.guavaRtrim(src);
+
+        // Compare the Strings obtained and the expected
+        Assert.assertTrue(ltrimResult.equalsIgnoreCase(ltrim));
+
+        Assert.assertTrue(rtrimResult.equalsIgnoreCase(rtrim));
+    }
+
+    @Test
+    public void givenString_whenCallingStringUtilsStripStartEnd_thenReturnsTrue() {
+        // Use StringUtils containsIgnoreCase to avoid case insensitive issues
+        String ltrim = LTrimRTrim.stringUtilsLTrim(src);
+        String rtrim = LTrimRTrim.stringUtilsRTrim(src);
+
+        // Compare the Strings obtained and the expected
+        Assert.assertTrue(ltrimResult.equalsIgnoreCase(ltrim));
+
+        Assert.assertTrue(rtrimResult.equalsIgnoreCase(rtrim));
+    }
+
+}