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package com.google.auth.oauth2;

import static org.junit.Assert.assertEquals;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public final class DefaultPKCEProviderTest {
  @Test
  public void testPkceExpected() throws NoSuchAlgorithmException {
    PKCEProvider pkce = new DefaultPKCEProvider();

    byte[] bytes = pkce.getCodeVerifier().getBytes();
    MessageDigest md = MessageDigest.getInstance("SHA-256");
    md.update(bytes);

    byte[] digest = md.digest();

    String expectedCodeChallenge = Base64.getUrlEncoder().encodeToString(digest);
    String expectedCodeChallengeMethod = "S256";

    assertEquals(pkce.getCodeChallenge(), expectedCodeChallenge);
    assertEquals(pkce.getCodeChallengeMethod(), expectedCodeChallengeMethod);
  }
}