Package org.hamcrest

Class CoreMatchers

java.lang.Object
org.hamcrest.CoreMatchers

public class CoreMatchers extends Object
Builder methods for various matchers.

CodeMatchers provides syntactic sugar for building matchers, or chains of matchers. By using static imports on these methods, concise and readable code calling the matchers can be maintained.

  • Method Details

    • allOf

      public static <T> Matcher<T> allOf(Iterable<Matcher<? super T>> matchers)
      Creates a matcher that matches if the examined object matches ALL of the specified matchers. For example:
      assertThat("myValue", allOf(startsWith("my"), containsString("Val")))
      Type Parameters:
      T - the matcher type.
      Parameters:
      matchers - all the matchers must pass.
      Returns:
      The matcher.
    • allOf

      @SafeVarargs public static <T> Matcher<T> allOf(Matcher<? super T>... matchers)
      Creates a matcher that matches if the examined object matches ALL of the specified matchers. For example:
      assertThat("myValue", allOf(startsWith("my"), containsString("Val")))
      Type Parameters:
      T - the matcher type.
      Parameters:
      matchers - all the matchers must pass.
      Returns:
      The matcher.
    • anyOf

      public static <T> AnyOf<T> anyOf(Iterable<Matcher<? super T>> matchers)
      Creates a matcher that matches if the examined object matches ANY of the specified matchers. For example:
      assertThat("myValue", anyOf(startsWith("foo"), containsString("Val")))
      Type Parameters:
      T - the matcher type.
      Parameters:
      matchers - any the matchers must pass.
      Returns:
      The matcher.
    • anyOf

      @SafeVarargs public static <T> AnyOf<T> anyOf(Matcher<? super T>... matchers)
      Creates a matcher that matches if the examined object matches ANY of the specified matchers. For example:
      assertThat("myValue", anyOf(startsWith("foo"), containsString("Val")))
      Type Parameters:
      T - the matcher type.
      Parameters:
      matchers - any the matchers must pass.
      Returns:
      The matcher.
    • both

      public static <LHS> CombinableMatcher.CombinableBothMatcher<LHS> both(Matcher<? super LHS> matcher)
      Creates a matcher that matches when both of the specified matchers match the examined object. For example:
      assertThat("fab", both(containsString("a")).and(containsString("b")))
      Type Parameters:
      LHS - the matcher type.
      Parameters:
      matcher - the matcher to combine, and both must pass.
      Returns:
      The matcher.
    • either

      public static <LHS> CombinableMatcher.CombinableEitherMatcher<LHS> either(Matcher<? super LHS> matcher)
      Creates a matcher that matches when either of the specified matchers match the examined object. For example:
      assertThat("fan", either(containsString("a")).or(containsString("b")))
      Type Parameters:
      LHS - the matcher type.
      Parameters:
      matcher - the matcher to combine, and either must pass.
      Returns:
      The matcher.
    • describedAs

      public static <T> Matcher<T> describedAs(String description, Matcher<T> matcher, Object... values)
      Wraps an existing matcher, overriding its description with that specified. All other functions are delegated to the decorated matcher, including its mismatch description. For example:
      describedAs("a big decimal equal to %0", equalTo(myBigDecimal), myBigDecimal.toPlainString())
      Type Parameters:
      T - the matcher type.
      Parameters:
      description - the new description for the wrapped matcher
      matcher - the matcher to wrap
      values - optional values to insert into the tokenized description
      Returns:
      The matcher.
    • everyItem

      public static <U> Matcher<Iterable<? extends U>> everyItem(Matcher<U> itemMatcher)
      Creates a matcher for Iterables that only matches when a single pass over the examined Iterable yields items that are all matched by the specified itemMatcher. For example:
      assertThat(Arrays.asList("bar", "baz"), everyItem(startsWith("ba")))
      Type Parameters:
      U - the matcher type.
      Parameters:
      itemMatcher - the matcher to apply to every item provided by the examined Iterable
      Returns:
      The matcher.
    • is

      public static <T> Matcher<T> is(Matcher<T> matcher)
      Decorates another Matcher, retaining its behaviour, but allowing tests to be slightly more expressive. For example:
      assertThat(cheese, is(equalTo(smelly)))
      instead of:
      assertThat(cheese, equalTo(smelly))
      Type Parameters:
      T - the matcher type.
      Parameters:
      matcher - the matcher to wrap.
      Returns:
      The matcher.
    • is

      public static <T> Matcher<T> is(T value)
      A shortcut to the frequently used is(equalTo(x)). For example:
      assertThat(cheese, is(smelly))
      instead of:
      assertThat(cheese, is(equalTo(smelly)))
      Type Parameters:
      T - the matcher type.
      Parameters:
      value - the value to check.
      Returns:
      The matcher.
    • isA

      public static <T> Matcher<T> isA(Class<T> type)
      A shortcut to the frequently used is(instanceOf(SomeClass.class)). For example:
      assertThat(cheese, isA(Cheddar.class))
      instead of:
      assertThat(cheese, is(instanceOf(Cheddar.class)))
      Type Parameters:
      T - the matcher type.
      Parameters:
      type - the type to check.
      Returns:
      The matcher.
    • anything

      public static Matcher<Object> anything()
      Creates a matcher that always matches, regardless of the examined object.
      Returns:
      The matcher.
    • anything

      public static Matcher<Object> anything(String description)
      Creates a matcher that always matches, regardless of the examined object, but describes itself with the specified String.
      Parameters:
      description - a meaningful String used when describing itself
      Returns:
      The matcher.
    • hasItem

      public static <T> Matcher<Iterable<? super T>> hasItem(Matcher<? super T> itemMatcher)
      Creates a matcher for Iterables that only matches when a single pass over the examined Iterable yields at least one item that is matched by the specified itemMatcher. Whilst matching, the traversal of the examined Iterable will stop as soon as a matching item is found. For example:
      assertThat(Arrays.asList("foo", "bar"), hasItem(startsWith("ba")))
      Type Parameters:
      T - the matcher type.
      Parameters:
      itemMatcher - the matcher to apply to items provided by the examined Iterable
      Returns:
      The matcher.
    • hasItem

      public static <T> Matcher<Iterable<? super T>> hasItem(T item)
      Creates a matcher for Iterables that only matches when a single pass over the examined Iterable yields at least one item that is equal to the specified item. Whilst matching, the traversal of the examined Iterable will stop as soon as a matching item is found. For example:
      assertThat(Arrays.asList("foo", "bar"), hasItem("bar"))
      Type Parameters:
      T - the matcher type.
      Parameters:
      item - the item to compare against the items provided by the examined Iterable
      Returns:
      The matcher.
    • hasItems

      @SafeVarargs public static <T> Matcher<Iterable<T>> hasItems(Matcher<? super T>... itemMatchers)
      Creates a matcher for Iterables that matches when consecutive passes over the examined Iterable yield at least one item that is matched by the corresponding matcher from the specified itemMatchers. Whilst matching, each traversal of the examined Iterable will stop as soon as a matching item is found. For example:
      assertThat(Arrays.asList("foo", "bar", "baz"), hasItems(endsWith("z"), endsWith("o")))
      Type Parameters:
      T - the matcher type.
      Parameters:
      itemMatchers - the matchers to apply to items provided by the examined Iterable
      Returns:
      The matcher.
    • hasItems

      @SafeVarargs public static <T> Matcher<Iterable<T>> hasItems(T... items)
      Creates a matcher for Iterables that matches when consecutive passes over the examined Iterable yield at least one item that is equal to the corresponding item from the specified items. Whilst matching, each traversal of the examined Iterable will stop as soon as a matching item is found. For example:
      assertThat(Arrays.asList("foo", "bar", "baz"), hasItems("baz", "foo"))
      Type Parameters:
      T - the matcher type.
      Parameters:
      items - the items to compare against the items provided by the examined Iterable
      Returns:
      The matcher.
    • equalTo

      public static <T> Matcher<T> equalTo(T operand)
      Creates a matcher that matches when the examined object is logically equal to the specified operand, as determined by calling the Object.equals(java.lang.Object) method on the examined object.

      If the specified operand is null then the created matcher will only match if the examined object's equals method returns true when passed a null (which would be a violation of the equals contract), unless the examined object itself is null, in which case the matcher will return a positive match.

      The created matcher provides a special behaviour when examining Arrays, whereby it will match if both the operand and the examined object are arrays of the same length and contain items that are equal to each other (according to the above rules) in the same indexes.

      For example:
       assertThat("foo", equalTo("foo"));
       assertThat(new String[] {"foo", "bar"}, equalTo(new String[] {"foo", "bar"}));
       
      Type Parameters:
      T - the matcher type.
      Parameters:
      operand - the value to check.
      Returns:
      The matcher.
    • equalToObject

      public static Matcher<Object> equalToObject(Object operand)
      Creates an IsEqual matcher that does not enforce the values being compared to be of the same static type.
      Parameters:
      operand - the value to check.
      Returns:
      The matcher.
    • any

      public static <T> Matcher<T> any(Class<T> type)
      Creates a matcher that matches when the examined object is an instance of the specified type, as determined by calling the Class.isInstance(Object) method on that type, passing the examined object.

      The created matcher forces a relationship between specified type and the examined object, and should be used when it is necessary to make generics conform, for example in the JMock clause with(any(Thing.class))

      For example:
      assertThat(new Canoe(), any(Canoe.class));
      Type Parameters:
      T - the matcher type.
      Parameters:
      type - the type to check.
      Returns:
      The matcher.
    • instanceOf

      public static <T> Matcher<T> instanceOf(Class<?> type)
      Creates a matcher that matches when the examined object is an instance of the specified type, as determined by calling the Class.isInstance(Object) method on that type, passing the the examined object.

      The created matcher assumes no relationship between specified type and the examined object.

      For example:
      assertThat(new Canoe(), instanceOf(Paddlable.class));
      Type Parameters:
      T - the matcher type.
      Parameters:
      type - the type to check.
      Returns:
      The matcher.
    • not

      public static <T> Matcher<T> not(Matcher<T> matcher)
      Creates a matcher that wraps an existing matcher, but inverts the logic by which it will match. For example:
      assertThat(cheese, is(not(equalTo(smelly))))
      Type Parameters:
      T - the matcher type.
      Parameters:
      matcher - the matcher whose sense should be inverted
      Returns:
      The matcher.
    • not

      public static <T> Matcher<T> not(T value)
      A shortcut to the frequently used not(equalTo(x)). For example:
      assertThat(cheese, is(not(smelly)))
      instead of:
      assertThat(cheese, is(not(equalTo(smelly))))
      Type Parameters:
      T - the matcher type.
      Parameters:
      value - the value that any examined object should not equal
      Returns:
      The matcher.
    • notNullValue

      public static Matcher<Object> notNullValue()
      A shortcut to the frequently used not(nullValue()). For example:
      assertThat(cheese, is(notNullValue()))
      instead of:
      assertThat(cheese, is(not(nullValue())))
      Returns:
      The matcher.
    • notNullValue

      public static <T> Matcher<T> notNullValue(Class<T> type)
      A shortcut to the frequently used not(nullValue(X.class)). Accepts a single dummy argument to facilitate type inference.. For example:
      assertThat(cheese, is(notNullValue(X.class)))
      instead of:
      assertThat(cheese, is(not(nullValue(X.class))))
      Type Parameters:
      T - the matcher type.
      Parameters:
      type - dummy parameter used to infer the generic type of the returned matcher
      Returns:
      The matcher.
    • nullValue

      public static Matcher<Object> nullValue()
      Creates a matcher that matches if examined object is null. For example:
      assertThat(cheese, is(nullValue())
      Returns:
      The matcher.
    • nullValue

      public static <T> Matcher<T> nullValue(Class<T> type)
      Creates a matcher that matches if examined object is null. Accepts a single dummy argument to facilitate type inference. For example:
      assertThat(cheese, is(nullValue(Cheese.class))
      Type Parameters:
      T - the matcher type.
      Parameters:
      type - dummy parameter used to infer the generic type of the returned matcher
      Returns:
      The matcher.
    • sameInstance

      public static <T> Matcher<T> sameInstance(T target)
      Creates a matcher that matches only when the examined object is the same instance as the specified target object.
      Type Parameters:
      T - the matcher type.
      Parameters:
      target - the target instance against which others should be assessed
      Returns:
      The matcher.
    • theInstance

      public static <T> Matcher<T> theInstance(T target)
      Creates a matcher that matches only when the examined object is the same instance as the specified target object.
      Type Parameters:
      T - the matcher type.
      Parameters:
      target - the target instance against which others should be assessed
      Returns:
      The matcher.
    • containsString

      public static Matcher<String> containsString(String substring)
      Creates a matcher that matches if the examined String contains the specified String anywhere. For example:
      assertThat("myStringOfNote", containsString("ring"))
      Parameters:
      substring - the substring that the returned matcher will expect to find within any examined string
      Returns:
      The matcher.
    • containsStringIgnoringCase

      public static Matcher<String> containsStringIgnoringCase(String substring)
      Creates a matcher that matches if the examined String contains the specified String anywhere, ignoring case. For example:
      assertThat("myStringOfNote", containsStringIgnoringCase("Ring"))
      Parameters:
      substring - the substring that the returned matcher will expect to find within any examined string
      Returns:
      The matcher.
    • startsWith

      public static Matcher<String> startsWith(String prefix)

      Creates a matcher that matches if the examined String starts with the specified String.

      For example:
      assertThat("myStringOfNote", startsWith("my"))
      Parameters:
      prefix - the substring that the returned matcher will expect at the start of any examined string
      Returns:
      The matcher.
    • startsWithIgnoringCase

      public static Matcher<String> startsWithIgnoringCase(String prefix)

      Creates a matcher that matches if the examined String starts with the specified String, ignoring case

      For example:
      assertThat("myStringOfNote", startsWithIgnoringCase("My"))
      Parameters:
      prefix - the substring that the returned matcher will expect at the start of any examined string
      Returns:
      The matcher.
    • endsWith

      public static Matcher<String> endsWith(String suffix)
      Creates a matcher that matches if the examined String ends with the specified String. For example:
      assertThat("myStringOfNote", endsWith("Note"))
      Parameters:
      suffix - the substring that the returned matcher will expect at the end of any examined string
      Returns:
      The matcher.
    • endsWithIgnoringCase

      public static Matcher<String> endsWithIgnoringCase(String suffix)
      Creates a matcher that matches if the examined String ends with the specified String, ignoring case. For example:
      assertThat("myStringOfNote", endsWithIgnoringCase("note"))
      Parameters:
      suffix - the substring that the returned matcher will expect at the end of any examined string
      Returns:
      The matcher.