How to assert greater than using JUnit Assert?

I have these values coming from a test

previousTokenValues[1] = "1378994409108"
currentTokenValues[1] = "1378994416509"

and I try

    // current timestamp is greater
    assertTrue(Long.parseLong(previousTokenValues[1]) > Long.parseLong(currentTokenValues[1]));

I get the java.lang.AssertionError and detailMessage on debugging is null.

How can I assert greater than conditions in using JUnit

Just how you've done it. assertTrue(boolean) also has an overload assertTrue(String, boolean) where the String is the message in case of failure; you can use that if you want to print that such-and-such wasn't greater than so-and-so.

You could also add hamcrest-all as a dependency to use matchers. See https://code.google.com/p/hamcrest/wiki/Tutorial:

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.*;

assertThat("timestamp",
           Long.parseLong(previousTokenValues[1]),
           greaterThan(Long.parseLong(currentTokenValues[1])));

That gives an error like:

java.lang.AssertionError: timestamp
Expected: a value greater than <456L>
     but: <123L> was less than <456L>

When using JUnit asserts, I always make the message nice and clear. It saves huge amounts of time debugging. Doing it this way avoids having to add a added dependency on hamcrest Matchers.

previousTokenValues[1] = "1378994409108";
currentTokenValues[1] = "1378994416509";

Long prev = Long.parseLong(previousTokenValues[1]);
Long curr = Long.parseLong(currentTokenValues[1]);
assertTrue("Previous (" + prev + ") should be greater than current (" + curr + ")", prev > curr);

you can also try below simple soln:

previousTokenValues[1] = "1378994409108";
currentTokenValues[1] = "1378994416509";

Long prev = Long.parseLong(previousTokenValues[1]);
Long curr = Long.parseLong(currentTokenValues[1]);

Assert.assertTrue(prev  > curr );	

You should add Hamcrest-library to your Build Path. It contains the needed Matchers.class which has the lessThan() method.

Dependency as below.

<dependency>
  <groupId>org.hamcrest</groupId>
  <artifactId>hamcrest-library</artifactId>
  <version>1.3</version>
  <scope>test</scope>
</dependency>

Alternatively if adding extra library such as hamcrest is not desirable, the logic can be implemented as utility method using junit dependency only:

public static void assertGreaterThan(int greater, int lesser) {
    assertGreaterThan(greater, lesser, null);
}

public static void assertGreaterThan(int greater, int lesser, String message) {
    if (greater <= lesser) {
        fail((StringUtils.isNotBlank(message) ? message + " ==> " : "") +
                "Expected: a value greater than <" + lesser + ">\n" +
                "But <" + greater + "> was " + (greater == lesser ? "equal to" : "less than") + " <" + lesser + ">");
    }
}

As I recognize, at the moment, in JUnit, the syntax is like this:

AssertTrue(Long.parseLong(previousTokenValues[1]) > Long.parseLong(currentTokenValues[1]), "your fail message ");

Means that, the condition is in front of the message.

assertTrue("your message", previousTokenValues[1].compareTo(currentTokenValues[1]) > 0)

this passes for previous > current values

You can put it like this

  assertTrue("your fail message ",Long.parseLong(previousTokenValues[1]) > Long.parseLong(currentTokenValues[1]));