OnJava8-Examples/validating/tests/DynamicStringInverterTests.java

// validating/tests/DynamicStringInverterTests.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
package validating;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
import org.junit.jupiter.api.*;
import static org.junit.jupiter.api.Assertions.*;
import static org.junit.jupiter.api.DynamicTest.*;

class DynamicStringInverterTests {
  // Combine operations to prevent code duplication:
  Stream<DynamicTest> testVersions(String id,
    Function<StringInverter, String> test) {
    List<StringInverter> versions = Arrays.asList(
      new Inverter1(), new Inverter2(),
      new Inverter3(), new Inverter4());
    return DynamicTest.stream(
      versions.iterator(),
      inverter -> inverter.getClass().getSimpleName(),
      inverter -> {
        System.out.println(
          inverter.getClass().getSimpleName() +
            ": " + id);
        try {
          if(test.apply(inverter) != "fail")
            System.out.println("Success");
        } catch(Exception | Error e) {
          System.out.println(
            "Exception: " + e.getMessage());
        }
      }
    );
  }
  String isEqual(String lval, String rval) {
    if(lval.equals(rval))
      return "success";
    System.out.println("FAIL: " + lval + " != " + rval);
    return "fail";
  }
  @BeforeAll
  static void startMsg() {
    System.out.println(
      ">>> Starting DynamicStringInverterTests <<<");
  }
  @AfterAll
  static void endMsg() {
    System.out.println(
      ">>> Finished DynamicStringInverterTests <<<");
  }
  @TestFactory
  Stream<DynamicTest> basicInversion1() {
    String in =  "Exit, Pursued by a Bear.";
    String out = "eXIT, pURSUED BY A bEAR.";
    return testVersions(
      "Basic inversion (should succeed)",
      inverter -> isEqual(inverter.invert(in), out)
    );
  }
  @TestFactory
  Stream<DynamicTest> basicInversion2() {
    return testVersions(
      "Basic inversion (should fail)",
      inverter -> isEqual(inverter.invert("X"), "X"));
  }
  @TestFactory
  Stream<DynamicTest> disallowedCharacters() {
    String disallowed = ";-_()*&^%$#@!~`0123456789";
    return testVersions(
      "Disallowed characters",
      inverter -> {
        String result = disallowed.chars()
          .mapToObj(c -> {
            String cc = Character.toString((char)c);
            try {
              inverter.invert(cc);
              return "";
            } catch(RuntimeException e) {
              return cc;
            }
          }).collect(Collectors.joining(""));
        if(result.length() == 0)
          return "success";
        System.out.println("Bad characters: " + result);
        return "fail";
      }
    );
  }
  @TestFactory
  Stream<DynamicTest> allowedCharacters() {
    String lowcase = "abcdefghijklmnopqrstuvwxyz ,.";
    String upcase =  "ABCDEFGHIJKLMNOPQRSTUVWXYZ ,.";
    return testVersions(
      "Allowed characters (should succeed)",
      inverter -> {
        assertEquals(inverter.invert(lowcase), upcase);
        assertEquals(inverter.invert(upcase), lowcase);
        return "success";
      }
    );
  }
  @TestFactory
  Stream<DynamicTest> lengthNoGreaterThan30() {
    String str = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
    assertTrue(str.length() > 30);
    return testVersions(
      "Length must be less than 31 (throws exception)",
      inverter -> inverter.invert(str)
    );
  }
  @TestFactory
  Stream<DynamicTest> lengthLessThan31() {
    String str = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
    assertTrue(str.length() < 31);
    return testVersions(
      "Length must be less than 31 (should succeed)",
      inverter -> inverter.invert(str)
    );
  }
}