src/main/java/org/fest/assertions/StringAssert.java
public @NotNull StringAssert doesNotContain(@NotNull String text) {
    checkNotNull(text);
    isNotNull();
    if (!actual.contains(text)) {
      return this;
    }
    failIfCustomMessageIsSet();
    throw failure(format("<%s> should not contain <%s>", actual, text));
  }
public @NotNull StringAssert doesNotContain(@NotNull String text) {
    checkNotNull(text);
    isNotNull();
    if (!actual.contains(text)) {
      return this;
    }
    failIfCustomMessageIsSet();
    throw failure(format("<%s> should not contain <%s>", actual, text));
  }
Verifies that the actual {@code String} does not contain the given text.

@param text the given text.
@return this assertion object.
@throws AssertionError       if the actual {@code String} is {@code null}.
@throws AssertionError       if the actual {@code String} contains the given text.
@throws NullPointerException if the given {@code String} is {@code null}.
@since 1.3