src/main/java/org/fest/assertions/GroupAssert.java
public final @NotNull S hasSize(int expected) {
    isNotNull();
    int size = actualGroupSize();
    if (size == expected) {
      return myself();
    }
    failIfCustomMessageIsSet();
    throw failure(format("expected size:<%s> but was:<%s> for <%s>", expected, size, actual));
  }
public final @NotNull S hasSize(int expected) {
    isNotNull();
    int size = actualGroupSize();
    if (size == expected) {
      return myself();
    }
    failIfCustomMessageIsSet();
    throw failure(format("expected size:<%s> but was:<%s> for <%s>", expected, size, actual));
  }
Verifies that the number of values in the actual group is equal to the given one.

@param expected the expected number of values in the actual group.
@return this assertion object.
@throws AssertionError if the number of values of the actual group is not equal to the given one.