Add tests for PasswordGen (#3163)

src/test/java/com/thealgorithms/others/PasswordGenTest.java

@@ -0,0 +1,37 @@
+package com.thealgorithms.others;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+
+public class PasswordGenTest {
+    @Test 
+    public void failGenerationWithSameMinMaxLengthTest() {
+        int length = 10;
+        assertThrows(IllegalArgumentException.class, ()-> {
+            PasswordGen.generatePassword(length, length);
+        });
+    }
+
+    @Test
+    public void generateOneCharacterPassword() {
+        String tempPassword = PasswordGen.generatePassword(1, 2);
+        assertTrue(tempPassword.length()==1);
+    }
+
+    @Test
+    public void failGenerationWithMinLengthSmallerThanMaxLengthTest() {
+        int minLength = 10;
+        int maxLength = 5;
+        assertThrows(IllegalArgumentException.class, ()-> {
+            PasswordGen.generatePassword(minLength, maxLength);
+        });
+    }
+
+    @Test
+    public void generatePasswordNonEmptyTest() {
+        String tempPassword = PasswordGen.generatePassword(8, 16);
+        assertTrue(tempPassword.length()!=0);
+    }
+}