feat: kata/regex-password-validation

kata/5-kyu/index.md

@@ -38,6 +38,7 @@
 - [Pick peaks](pick-peaks "5279f6fe5ab7f447890006a7")
 - [Primes in numbers](primes-in-numbers "54d512e62a5e54c96200019e")
 - [Product of consecutive Fib numbers](product-of-consecutive-fib-numbers "5541f58a944b85ce6d00006a")
+- [Regex Password Validation](regex-password-validation "52e1476c8147a7547a000811")
 - [RGB To Hex Conversion](rgb-to-hex-conversion "513e08acc600c94f01000001")
 - [Rot13](rot13-1 "530e15517bc88ac656000716")
 - [ROT13](rot13 "52223df9e8f98c7aa7000062")

kata/5-kyu/regex-password-validation/README.md

@@ -0,0 +1,9 @@
+# [Regex Password Validation](https://www.codewars.com/kata/regex-password-validation "https://www.codewars.com/kata/52e1476c8147a7547a000811")
+
+You need to write regex that will validate a password to make sure it meets the following criteria:
+
+* At least six characters long
+* contains a lowercase letter
+* contains an uppercase letter
+* contains a digit
+* only contains alphanumeric characters (note that `'_'` is not alphanumeric)

kata/5-kyu/regex-password-validation/main/PasswordRegex.java

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+final class PasswordRegex {
+  static final String REGEX = "(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)[a-zA-Z\\d]{6,}";
+
+  private PasswordRegex() {}
+}

kata/5-kyu/regex-password-validation/test/SolutionTest.java

@@ -0,0 +1,41 @@
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class SolutionTest {
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "fjd3IR9",
+        "4fdg5Fj3",
+        "djI38D55",
+        "123abcABC",
+        "ABC123abc",
+        "Password123"
+    })
+    void valid(String password) {
+        assertTrue(password.matches(PasswordRegex.REGEX));
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "ghdfj32",
+        "DSJKHD23",
+        "dsF43",
+        "DHSJdhjsU",
+        "fjd3IR9.;",
+        "fjd3  IR9",
+        "djI3_8D55",
+        "@@",
+        "JHD5FJ53",
+        "!fdjn345",
+        "jfkdfj3j",
+        "123",
+        "abc",
+        ""
+    })
+    void invalid(String password) {
+        assertFalse(password.matches(PasswordRegex.REGEX));
+    }
+}