src/main/java/org/fest/assertions/FileAssert.java
public @NotNull FileAssert hasSameContentAs(@NotNull File expected) {
    checkNotNull(expected);
    isNotNull();
    assertExists(actual).assertExists(expected);
    try {
      LineDiff[] diffs = comparator.compareContents(actual, expected);
      if (!isNullOrEmpty(diffs)) {
        fail(expected, diffs);
      }
    } catch (IOException e) {
      cannotCompareToExpectedFile(expected, e);
    }
    return this;
  }
public @NotNull FileAssert hasSameContentAs(@NotNull File expected) {
    checkNotNull(expected);
    isNotNull();
    assertExists(actual).assertExists(expected);
    try {
      LineDiff[] diffs = comparator.compareContents(actual, expected);
      if (!isNullOrEmpty(diffs)) {
        fail(expected, diffs);
      }
    } catch (IOException e) {
      cannotCompareToExpectedFile(expected, e);
    }
    return this;
  }
Verifies that the content of the actual {@code File} is equal to the content of the given one. Adapted from <a
href="http://junit-addons.sourceforge.net/junitx/framework/FileAssert.html" target="_blank">FileAssert</a> (from <a
href="http://sourceforge.net/projects/junit-addons">JUnit-addons</a>.)

@param expected the given {@code File} to compare the actual {@code File} to.
@return this assertion object.
@throws NullPointerException if the file to compare to is {@code null}.
@throws AssertionError       if the the actual {@code File} is {@code null}.
@throws AssertionError       if the content of the actual {@code File} is not equal to the content of the given one.