matcher library Null safety

Support for specifying test expectations, such as for unit tests.

Classes

CustomMatcher
A useful utility class for implementing other matchers through inheritance. Derived classes should call the base constructor with a feature name and description, and an instance matcher, and should implement the featureValueOf abstract method.
Description
Matchers build up their error messages by appending to Description objects.
isInstanceOf<T>
DEPRECATED Use isA instead.
Matcher
The base class for all matchers.
StringDescription
The default implementation of Description. This should rarely need substitution, although conceivably it is a place where other languages could be supported.
TypeMatcher<T>
A Matcher subclass that supports validating the Type of the target object.

Constants

anything → const Matcher
A matcher that matches any value.
_IsAnything()
isArgumentError → const TypeMatcher<ArgumentError>
A matcher for ArgumentError.
TypeMatcher<ArgumentError>()
isCastError → const TypeMatcher<CastError>
A matcher for CastError.
Deprecated('CastError has been deprecated in favor of TypeError. ' 'Use `isA<TypeError>()` or, if you need compatibility with older SDKs, ' 'use `isA<CastError>()` and ignore the deprecation.')">@Deprecated('CastError has been deprecated in favor of TypeError. ' 'Use `isA<TypeError>()` or, if you need compatibility with older SDKs, ' 'use `isA<CastError>()` and ignore the deprecation.')
TypeMatcher<CastError>()
isConcurrentModificationError → const TypeMatcher<ConcurrentModificationError>
A matcher for ConcurrentModificationError.
TypeMatcher<ConcurrentModificationError>()
isCyclicInitializationError → const TypeMatcher<CyclicInitializationError>
A matcher for CyclicInitializationError.
TypeMatcher<CyclicInitializationError>()
isEmpty → const Matcher
Returns a matcher that matches the isEmpty property.
_Empty()
isException → const TypeMatcher<Exception>
A matcher for Exception.
TypeMatcher<Exception>()
isFalse → const Matcher
A matcher that matches anything except the Boolean value true.
_IsFalse()
isFormatException → const TypeMatcher<FormatException>
A matcher for FormatException.
TypeMatcher<FormatException>()
isList → const TypeMatcher<List>
A matcher for List.
TypeMatcher<List>()
isMap → const TypeMatcher<Map>
A matcher for Map.
TypeMatcher<Map>()
isNaN → const Matcher
A matcher that matches the numeric value NaN.
_IsNaN()
isNegative → const Matcher
A matcher which matches if the match argument is negative.
_OrderingMatcher(0, false, true, false, 'a negative value', false)
isNonNegative → const Matcher
A matcher which matches if the match argument is zero or positive.
_OrderingMatcher(0, true, false, true, 'a non-negative value', false)
isNonPositive → const Matcher
A matcher which matches if the match argument is zero or negative.
_OrderingMatcher(0, true, true, false, 'a non-positive value', false)
isNonZero → const Matcher
A matcher which matches if the match argument is non-zero.
_OrderingMatcher(0, false, true, true, 'a value not equal to')
isNoSuchMethodError → const TypeMatcher<NoSuchMethodError>
A matcher for NoSuchMethodError.
TypeMatcher<NoSuchMethodError>()
isNotEmpty → const Matcher
Returns a matcher that matches the isNotEmpty property.
_NotEmpty()
isNotNaN → const Matcher
A matcher that matches any non-NaN value.
_IsNotNaN()
isNotNull → const Matcher
A matcher that matches any non-null value.
_IsNotNull()
isNull → const Matcher
A matcher that matches any null value.
_IsNull()
isNullThrownError → const TypeMatcher<NullThrownError>
A matcher for NullThrownError.
TypeMatcher<NullThrownError>()
isPositive → const Matcher
A matcher which matches if the match argument is positive.
_OrderingMatcher(0, false, false, true, 'a positive value', false)
isRangeError → const TypeMatcher<RangeError>
A matcher for RangeError.
TypeMatcher<RangeError>()
isStateError → const TypeMatcher<StateError>
A matcher for StateError.
TypeMatcher<StateError>()
isTrue → const Matcher
A matcher that matches the Boolean value true.
_IsTrue()
isUnimplementedError → const TypeMatcher<UnimplementedError>
A matcher for UnimplementedError.
TypeMatcher<UnimplementedError>()
isUnsupportedError → const TypeMatcher<UnsupportedError>
A matcher for UnsupportedError.
TypeMatcher<UnsupportedError>()
isZero → const Matcher
A matcher which matches if the match argument is zero.
_OrderingMatcher(0, true, false, false, 'a value equal to')
returnsNormally → const Matcher
A matcher that matches a function call against no exception.
_ReturnsNormally()

Functions

addStateInfo(Map matchState, Map values) → void
Useful utility for nesting match states.
allOf(Object? arg0, [Object? arg1, Object? arg2, Object? arg3, Object? arg4, Object? arg5, Object? arg6]) → Matcher
This returns a matcher that matches if all of the matchers passed as arguments (up to 7) match.
anyElement(Object? valueOrMatcher) → Matcher
Returns a matcher which matches Iterables in which at least one element matches the given valueOrMatcher.
anyOf(Object? arg0, [Object? arg1, Object? arg2, Object? arg3, Object? arg4, Object? arg5, Object? arg6]) → Matcher
Matches if any of the given matchers evaluate to true.
closeTo(num value, num delta) → Matcher
Returns a matcher which matches if the match argument is within delta of some value.
collapseWhitespace(String string) → String
Utility function to collapse whitespace runs to single spaces and strip leading/trailing whitespace.
contains(Object? expected) → Matcher
Returns a matcher that matches if the match argument contains the expected value.
containsAll(Iterable expected) → Matcher
Matches Iterables which contain an element matching every value in expected in any order, and may contain additional values.
containsAllInOrder(Iterable expected) → Matcher
Matches Iterables which contain an element matching every value in expected in the same order, but may contain additional values interleaved throughout.
containsPair(Object? key, Object? valueOrMatcher) → Matcher
Returns a matcher which matches maps containing the key-value pair with key => valueOrMatcher.
containsValue(Object? value) → Matcher
Returns a matcher which matches maps containing the given value.
endsWith(String suffixString) → Matcher
Returns a matcher that matches if the match argument is a string and ends with suffixString.
equals(Object? expected, [int limit = 100]) → Matcher
Returns a matcher that matches if the value is structurally equal to expected.
equalsIgnoringCase(String value) → Matcher
Returns a matcher which matches if the match argument is a string and is equal to value when compared case-insensitively.
equalsIgnoringWhitespace(String value) → Matcher
Returns a matcher which matches if the match argument is a string and is equal to value, ignoring whitespace.
escape(String str) → String
Returns str with all whitespace characters represented as their escape sequences.
everyElement(Object? valueOrMatcher) → Matcher
Returns a matcher which matches Iterables in which all elements match the given valueOrMatcher.
greaterThan(Object value) → Matcher
Returns a matcher which matches if the match argument is greater than the given value.
greaterThanOrEqualTo(Object value) → Matcher
Returns a matcher which matches if the match argument is greater than or equal to the given value.
hasLength(Object? matcher) → Matcher
Returns a matcher that matches if an object has a length property that matches matcher.
inClosedOpenRange(num low, num high) → Matcher
Returns a matcher which matches if the match argument is greater than or equal to a low and less than high.
inExclusiveRange(num low, num high) → Matcher
Returns a matcher which matches if the match argument is greater than low and less than high.
inInclusiveRange(num low, num high) → Matcher
Returns a matcher which matches if the match argument is greater than or equal to low and less than or equal to high.
inOpenClosedRange(num low, num high) → Matcher
Returns a matcher which matches if the match argument is greater than low and less than or equal to high.
isA<T>() → TypeMatcher<T>
Returns a matcher that matches objects with type T.
isIn(Object? expected) → Matcher
Returns a matcher that matches if the match argument is in the expected value. This is the converse of contains.
isNot(Object? valueOrMatcher) → Matcher
Returns a matcher that inverts valueOrMatcher to its logical negation.
lessThan(Object value) → Matcher
Returns a matcher which matches if the match argument is less than the given value.
lessThanOrEqualTo(Object value) → Matcher
Returns a matcher which matches if the match argument is less than or equal to the given value.
matches(Pattern re) → Matcher
Returns a matcher that matches if the match argument is a string and matches the regular expression given by re.
orderedEquals(Iterable expected) → Matcher
Returns a matcher which matches Iterables that have the same length and the same elements as expected, in the same order.
pairwiseCompare<S, T>(Iterable<S> expected, bool comparator(S, T), String description) → Matcher
A pairwise matcher for Iterables.
predicate<T>(bool f(T), [String description = 'satisfies function']) → Matcher
Returns a matcher that uses an arbitrary function that returns true or false for the actual value.
same(Object? expected) → Matcher
Returns a matches that matches if the value is the same instance as expected, using identical.
startsWith(String prefixString) → Matcher
Returns a matcher that matches if the match argument is a string and starts with prefixString.
stringContainsInOrder(List<String> substrings) → Matcher
Returns a matcher that matches if the match argument is a string and contains a given list of substrings in relative order.
unorderedEquals(Iterable expected) → Matcher
Returns a matcher which matches Iterables that have the same length and the same elements as expected, but not necessarily in the same order.
unorderedMatches(Iterable expected) → Matcher
Returns a matcher which matches Iterables whose elements match the matchers in expected, but not necessarily in the same order.
wrapMatcher(Object? valueOrMatcher) → Matcher
Takes an argument and returns an equivalent Matcher.