src/main/java/org/fest/assertions/internal/Doubles.java
public void assertEqual(Description description, Double actual, Double expected, Offset<Double> offset) {
    checkOffsetIsNotNull(offset);
    checkNumberIsNotNull(expected);
    assertNotNull(description, actual);
    if (!isEqualTo(actual, expected, offset)) {
      throw failures.failure(description,
          shouldBeEqual(actual, expected, offset, abs(expected.doubleValue() - actual.doubleValue())));
    }
  }
public void assertEqual(Description description, Double actual, Double expected, Offset<Double> offset) {
    checkOffsetIsNotNull(offset);
    checkNumberIsNotNull(expected);
    assertNotNull(description, actual);
    if (!isEqualTo(actual, expected, offset)) {
      throw failures.failure(description,
          shouldBeEqual(actual, expected, offset, abs(expected.doubleValue() - actual.doubleValue())));
    }
  }
Verifies that two doubles are equal within a positive offset.<br>
It does not rely on the custom comparisonStrategy (if one is set) because using an offset is already a specific
comparison strategy.

@param description describes the information about the assertion.
@param actual the <em>actual</em> value.
@param expected the <em>expected</em> value.
@param offset the given positive <em>offset</em>.
@throws NullPointerException if the given <em>offset</em> is {@code null}.
@throws AssertionError if the <em>actual</em> value is {@code null}.
@throws AssertionError if the <em>actual</em> value is not equal to the <em>expected</em> one.