BAEL-5277 tests added

core-java-modules/core-java-string-algorithms-3/pom.xml

@@ -24,6 +24,11 @@
             <artifactId>commons-validator</artifactId>
             <version>${validator.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${apache-commons-lang3.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -51,6 +56,7 @@
     <properties>
         <guava.version>31.0.1-jre</guava.version>
         <validator.version>1.7</validator.version>
+        <apache-commons-lang3.version>3.12.0</apache-commons-lang3.version>
     </properties>
 
 </project>

core-java-modules/core-java-string-algorithms-3/src/test/java/com/baeldung/generator/NCharStringGeneratorUnitTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.generator;
+
+import org.apache.commons.lang3.RandomStringUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.stream.Collectors;
+
+import com.google.common.base.Joiner;
+import com.google.common.base.Strings;
+
+import static ch.qos.logback.core.CoreConstants.EMPTY_STRING;
+import static java.util.stream.Stream.generate;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class NCharStringGeneratorUnitTest {
+
+    private static final String EXPECTED_STRING = "aaaaaaa";
+    private static final int N = 7;
+
+    @Test
+    void givenString_whenApacheStringUtilsUsed_thenStringCreated() {
+        char charToAppend = 'a';
+        String newString = StringUtils.repeat(charToAppend, N);
+        assertEquals(EXPECTED_STRING, newString);
+    }
+
+    @Test
+    void givenString_whenGuavaRepeatUsed_thenStringCreated() {
+        String charToAppend = "a";
+        String newString = Strings.repeat(charToAppend, N);
+        assertEquals(EXPECTED_STRING, newString);
+    }
+
+    @Test
+    void givenString_whenArraysFillUsed_thenStringCreated() {
+        char charToAppend = 'a';
+        char[] charArray = new char[N];
+        Arrays.fill(charArray, charToAppend);
+        String newString = new String(charArray);
+        assertEquals(EXPECTED_STRING, newString);
+    }
+
+    @Test
+    void givenString_whenGenerateAndJoiningUsed_thenStringCreated() {
+        String charToAppend = "a";
+        String newString = generate(() -> charToAppend).limit(N).collect(Collectors.joining());
+        assertEquals(EXPECTED_STRING, newString);
+    }
+
+    @Test
+    void givenString_whenStringJoinUsed_thenStringCreated() {
+        String charToAppend = "a";
+        String newString = String.join(EMPTY_STRING, Collections.nCopies(N, charToAppend));
+        assertEquals(EXPECTED_STRING, newString);
+    }
+
+    @Test
+    void givenString_whenGuavaJoinerUsed_thenStringCreated() {
+        String charToAppend = "a";
+        String newString = Joiner.on(EMPTY_STRING).join(Collections.nCopies(N, charToAppend));
+        assertEquals(EXPECTED_STRING, newString);
+    }
+
+    @Test
+    void givenString_whenRandomStringUtilsUsed_thenStringCreated() {
+        String charToAppend = "a";
+        String newString = RandomStringUtils.random(N, charToAppend);
+        assertEquals(EXPECTED_STRING, newString);
+    }
+}