Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that B is implicitly convertible to A, given an implicit Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that B is implicitly convertible to A, given an implicit Equality[A].
The implicitly passed Equality[A] must be used to determine equality by the returned EqualityConstraint's
areEqual method.
This method is overridden and made implicit by subtraits
ConversionCheckedTripleEquals) and
ConversionCheckedLegacyTripleEquals, and
overriden as non-implicit by the other subtraits in this package.
an Equality[A] type class to which the EqualityConstraint.areEqual method will delegate to determine equality.
an implicit conversion from B to A
an EqualityConstraint[A, B] whose areEqual method delegates to the areEqual method of
the passed Equality[A].
Convert to an CheckingEqualizer that provides === and !== operators that result in Boolean and enforce a type constraint.
Convert to an CheckingEqualizer that provides === and !== operators that result in Boolean and enforce a type constraint.
This method is overridden and made implicit by subtraits TypeCheckedTripleEquals and ConversionCheckedTripleEquals, and overriden as
non-implicit by the other subtraits in this package.
the object whose type to convert to CheckingEqualizer.
if left is null.
Convert to an Equalizer that provides === and !== operators that
result in Boolean and enforce no type constraint.
Convert to an Equalizer that provides === and !== operators that
result in Boolean and enforce no type constraint.
This method is overridden and made implicit by subtrait TripleEquals and overriden as non-implicit by the other subtraits in this package.
the object whose type to convert to Equalizer.
if left is null.
Convert to a LegacyCheckingEqualizer that provides === and !== operators that result in Option[String] and
enforce a type constraint.
Convert to a LegacyCheckingEqualizer that provides === and !== operators that result in Option[String] and
enforce a type constraint.
This method is overridden and made implicit by subtraits TypeCheckedLegacyTripleEquals and ConversionCheckedLegacyTripleEquals, and
overriden as non-implicit by the other subtraits in this package.
the object whose type to convert to LegacyCheckingEqualizer.
if left is null.
Convert to a LegacyEqualizer that provides === and !== operators that
result in Option[String] and enforce no type constraint.
Convert to a LegacyEqualizer that provides === and !== operators that
result in Option[String] and enforce no type constraint.
This method is overridden and made implicit by subtrait LegacyTripleEquals and overriden as non-implicit by the other subtraits in this package.
the object whose type to convert to LegacyEqualizer.
if left is null.
Return an Equality[A] for any type A that determines equality via the == operator on type A.
Return an Equality[A] for any type A that determines equality via the == operator on type A.
a DefaultEquality for type A
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that A is implicitly convertible to B, given an implicit Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that A is implicitly convertible to B, given an implicit Equality[A].
The implicitly passed Equality[A] must be used to determine equality by the returned EqualityConstraint's
areEqual method.
This method is overridden and made implicit by subtraits
LowPriorityConversionCheckedConstraint (extended by
ConversionCheckedTripleEquals), and
LowPriorityConversionCheckedLegacyConstraint (extended by
ConversionCheckedLegacyTripleEquals), and
overriden as non-implicit by the other subtraits in this package.
an implicit conversion from A to B
an EqualityConstraint[A, B] whose areEqual method delegates to the areEqual method of
the passed Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an implicit Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an implicit Equality[A].
The implicitly passed Equality[A] must be used to determine equality by the returned EqualityConstraint's
areEqual method.
This method is overridden and made implicit by subtraits
LowPriorityTypeCheckedConstraint (extended by
TypeCheckedTripleEquals), and
LowPriorityTypeCheckedLegacyConstraint (extended by
TypeCheckedLegacyTripleEquals), and
overriden as non-implicit by the other subtraits in this package.
an Equality[A] type class to which the EqualityConstraint.areEqual method
will delegate to determine equality.
evidence that A is a subype of B
an EqualityConstraint[A, B] whose areEqual method delegates to the
areEqual method of the passed Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an implicit Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an implicit Equality[A].
The implicitly passed Equality[A] must be used to determine equality by the returned EqualityConstraint's
areEqual method.
This method is overridden and made implicit by subtraits
TypeCheckedTripleEquals) and
TypeCheckedLegacyTripleEquals, and
overriden as non-implicit by the other subtraits in this package.
an Equality[A] type class to which the EqualityConstraint.areEqual method will delegate to determine equality.
evidence that B is a subype of A
an EqualityConstraint[A, B] whose areEqual method delegates to the areEqual method of
the passed Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, with no type constraint enforced, given an
implicit Equality[A].
Provides an EqualityConstraint[A, B] class for any two types A and B, with no type constraint enforced, given an
implicit Equality[A].
The implicitly passed Equality[A] must be used to determine equality by the returned EqualityConstraint's
areEqual method.
This method is overridden and made implicit by subtraits TripleEquals and LegacyTripleEquals, and
overriden as non-implicit by the other subtraits in this package.
an Equality[A] type class to which the EqualityConstraint.areEqual method will delegate to determine equality.
an EqualityConstraint[A, B] whose areEqual method delegates to the areEqual method of
the passed Equality[A].
Returns a TripleEqualsInvocationOnInterval[T], given an Interval[T], to facilitate
the “<left> should !== (<pivot> +- <tolerance>)”
syntax of Matchers.
Returns a TripleEqualsInvocationOnInterval[T], given an Interval[T], to facilitate
the “<left> should !== (<pivot> +- <tolerance>)”
syntax of Matchers.
the Interval[T] against which to compare the left-hand value
a TripleEqualsInvocationOnInterval wrapping the passed Interval[T] value, with
expectingEqual set to false.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should !== null” syntax
of Matchers.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should !== null” syntax
of Matchers.
a null reference
a TripleEqualsInvocation wrapping the passed null value, with expectingEqual
set to false.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should !== <right>” syntax
of Matchers.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should !== <right>” syntax
of Matchers.
the right-hand side value for an equality assertion
a TripleEqualsInvocation wrapping the passed right value, with expectingEqual
set to false.
Returns a TripleEqualsInvocationOnInterval[T], given an Interval[T], to facilitate
the “<left> should === (<pivot> +- <tolerance>)”
syntax of Matchers.
Returns a TripleEqualsInvocationOnInterval[T], given an Interval[T], to facilitate
the “<left> should === (<pivot> +- <tolerance>)”
syntax of Matchers.
the Interval[T] against which to compare the left-hand value
a TripleEqualsInvocationOnInterval wrapping the passed Interval[T] value, with
expectingEqual set to true.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should === null” syntax
of Matchers.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should === null” syntax
of Matchers.
a null reference
a TripleEqualsInvocation wrapping the passed null value, with expectingEqual
set to true.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should === <right>” syntax
of Matchers.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should === <right>” syntax
of Matchers.
the right-hand side value for an equality assertion
a TripleEqualsInvocation wrapping the passed right value, with expectingEqual
set to true.
Trait that defines abstract methods used to enforce compile-time type constraints for equality comparisons, and defines
===and!==operators used by matchers.This abstract methods of this trait are selectively implemented as implicit by subclasses to enable a spectrum of type constraints for the
===and!==operators. As an illustration, if in the expression,a === b, the type ofaisAandbisB, the following three levels of compile-time checking can be obtained fromEqualityConstraintssubtraits:Unchecked -
AandBcan be any two types. This (weakest) constraint level is available from subtraitsTripleEqualsandLegacyTripleEquals.Conversion checked -
Amust be a subtype ofB, or vice versa, or an implicit conversion must be available that convertsAtoB, or vice versa. (BothAandBcan be the same type, because a type is considered a subtype of itself.) This (intermediate) constraint level is available from subtraitsConversionCheckedTripleEqualsandConversionCheckedLegacyTripleEquals.Type checked -
Amust be a subtype ofB, or vice versa. (BothAandBcan be the same type, because a type is considered a subtype of itself.) This (strongest) constraint level is available from subtraitsTypeCheckedTripleEqualsandTypeCheckedLegacyTripleEquals.The difference between the regular and “legacy” variants of each pair of traits is that the
===and!==operators provided by the regular variants result inBoolean, whereas those of the legacy variants result inOption[String]. For example, were you to mix inTripleEquals, the expression1 + 1 === 3would returnfalse. Were you to mix inLegacyTripleEquals, by contrast, the expression1 + 1 === 3would returnSome("2 did not equal 3").The purpose of the legacy variants is to maintain compatibility with existing code that uses ScalaTest's original
===defined in traitorg.scalatest.Assertions. This===operator returned anOption[String]to facilitate better error messages. With the advent of macros in Scala 2.10, it is possible to obtain good error messages by makingasserta macro. Once ScalaTest no longer supports Scala 2.9, the legacy variants (LegacyTripleEquals,ConversionCheckedLegacyTripleEquals, andTypeCheckedLegacyTripleEquals) will be deprecated and eventually removed,===will return onlyBoolean, and good error messages will be obtained via macros.This trait defines all methods that need to be defined implicitly by the six subtraits so that if multiple subtraits are used together, the inner-most subtrait in scope can not only enable the implicits it needs by overriding or hiding those methods (currently-in-scope as regular, non-implicit methods) and making them implicit, it can also disable any implicits enabled by its sibling subtraits in enclosing scopes. For example, if your test class mixes in
TypeCheckedTripleEquals, inside your test class the following methods will be implicit:convertToCheckingEqualizetypeCheckedEqualityConstraintlowPriorityTypeCheckedEqualityConstraintIf in the body of a test you want to turn off the type checking, you can import the members of
TripleEqualsin the body of that test. This will not only hide non-implicit methodsconvertToEqualizerunconstrainedEqualityofTypeCheckedTripleEquals, replacing those with implicit ones defined inTripleEquals, it will also hide the three methods made implicit inTypeCheckedTripleEquals(and listed above), replacing them by non-implicit ones.In short, you should be able to select a primary constraint level via either a mixin or import, then change that in nested scopes however you want, again either through a mixin or import, without getting any implicit conversion ambiguity. The innermost constraint level in scope will always be in force.