ShouldMatchers

Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate the “<left> should !== (<pivot> +- <tolerance>)” syntax of Matchers.

Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate the “<left> should !== null” syntax of Matchers.

Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate the “<left> should !== <right>” syntax of Matchers.

This method enables the following syntax:

num should (not be < (10) and not be > (17))
                   ^

This method enables the following syntax:

num should (not be <= (10) and not be > (17))
                   ^

Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate the “<left> should === (<pivot> +- <tolerance>)” syntax of Matchers.

Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate the “<left> should === null” syntax of Matchers.

Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate the “<left> should === <right>” syntax of Matchers.

This method enables the following syntax:

num should (not be > (10) and not be < (7))
                   ^

This method enables the following syntax:

num should (not be >= (10) and not be < (7))
                   ^

This method enables the following syntax:

a [RuntimeException] should be thrownBy { ... }
^

This field enables the following syntax:

badBook should not be a ('goodRead)
                      ^

This field enables syntax such as the following:

result should equal ("hello") (after being lowerCased)
                               ^

This method enables the following syntax for String:

all(str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

all(jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

all(xs) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

List(1, 2, 3) should contain (allOf(1, 2))
                              ^

This method enables the following syntax:

an [Exception] should be thrownBy { ... }
^

This field enables the following syntax:

badBook should not be an (excellentRead)
                      ^

Assert that a boolean condition, described in String message, is true. If the condition is true, this method returns normally. Else, it throws TestFailedException with a helpful error message appended with the String obtained by invoking toString on the specified clue as the exception's detail message.

This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:

• assert(a == b, "a good clue")
• assert(a != b, "a good clue")
• assert(a === b, "a good clue")
• assert(a !== b, "a good clue")
• assert(a > b, "a good clue")
• assert(a >= b, "a good clue")
• assert(a < b, "a good clue")
• assert(a <= b, "a good clue")
• assert(a startsWith "prefix", "a good clue")
• assert(a endsWith "postfix", "a good clue")
• assert(a contains "something", "a good clue")
• assert(a eq b, "a good clue")
• assert(a ne b, "a good clue")
• assert(a > 0 && b > 5, "a good clue")
• assert(a > 0 || b > 5, "a good clue")
• assert(a.isEmpty, "a good clue")
• assert(!a.isEmpty, "a good clue")
• assert(a.isInstanceOf[String], "a good clue")
• assert(a.length == 8, "a good clue")
• assert(a.size == 8, "a good clue")
• assert(a.exists(_ == 8), "a good clue")

At this time, any other form of expression will just get a TestFailedException with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the === that returns Boolean, not Option[String] to be the default in tests. This makes === consistent between tests and production code. If you have pre-existing code you wrote under ScalaTest 1.x, in which you are expecting=== to return an Option[String], use can get that behavior back by mixing in trait LegacyTripleEquals.

Assert that a boolean condition is true. If the condition is true, this method returns normally. Else, it throws TestFailedException.

This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:

• assert(a == b)
• assert(a != b)
• assert(a === b)
• assert(a !== b)
• assert(a > b)
• assert(a >= b)
• assert(a < b)
• assert(a <= b)
• assert(a startsWith "prefix")
• assert(a endsWith "postfix")
• assert(a contains "something")
• assert(a eq b)
• assert(a ne b)
• assert(a > 0 && b > 5)
• assert(a > 0 || b > 5)
• assert(a.isEmpty)
• assert(!a.isEmpty)
• assert(a.isInstanceOf[String])
• assert(a.length == 8)
• assert(a.size == 8)
• assert(a.exists(_ == 8))

At this time, any other form of expression will get a TestFailedException with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the === that returns Boolean, not Option[String] to be the default in tests. This makes === consistent between tests and production code. If you have pre-existing code you wrote under ScalaTest 1.x, in which you are expecting=== to return an Option[String], use can get that behavior back by mixing in trait LegacyTripleEquals.

Asserts that a given string snippet of code passes both the Scala parser and type checker.

You can use this to make sure a snippet of code compiles:

assertCompiles("val a: Int = 1")

Although assertCompiles is implemented with a macro that determines at compile time whether the snippet of code represented by the passed string compiles, errors (i.e., snippets of code that do not compile) are reported as test failures at runtime.

Asserts that a given string snippet of code does not pass either the Scala parser or type checker.

Often when creating libraries you may wish to ensure that certain arrangements of code that represent potential “user errors” do not compile, so that your library is more error resistant. ScalaTest's Assertions trait includes the following syntax for that purpose:

assertDoesNotCompile("val a: String = \"a string")

Although assertDoesNotCompile is implemented with a macro that determines at compile time whether the snippet of code represented by the passed string doesn't compile, errors (i.e., snippets of code that do compile) are reported as test failures at runtime.

Note that the difference between assertTypeError and assertDoesNotCompile is that assertDoesNotCompile will succeed if the given code does not compile for any reason, whereas assertTypeError will only succeed if the given code does not compile because of a type error. If the given code does not compile because of a syntax error, for example, assertDoesNotCompile will return normally but assertTypeError will throw a TestFailedException.

Assert that the value passed as expected equals the value passed as actual. If the actual value equals the expected value (as determined by ==), assertResult returns normally. Else, assertResult throws a TestFailedException whose detail message includes the expected and actual values.

Assert that the value passed as expected equals the value passed as actual. If the actual equals the expected (as determined by ==), assertResult returns normally. Else, if actual is not equal to expected, assertResult throws a TestFailedException whose detail message includes the expected and actual values, as well as the String obtained by invoking toString on the passed clue.

Asserts that a given string snippet of code does not pass the Scala type checker, failing if the given snippet does not pass the Scala parser.

Often when creating libraries you may wish to ensure that certain arrangements of code that represent potential “user errors” do not compile, so that your library is more error resistant. ScalaTest's Assertions trait includes the following syntax for that purpose:

assertTypeError("val a: String = 1")

Although assertTypeError is implemented with a macro that determines at compile time whether the snippet of code represented by the passed string type checks, errors (i.e., snippets of code that do type check) are reported as test failures at runtime.

Note that the difference between assertTypeError and assertDoesNotCompile is that assertDoesNotCompile will succeed if the given code does not compile for any reason, whereas assertTypeError will only succeed if the given code does not compile because of a type error. If the given code does not compile because of a syntax error, for example, assertDoesNotCompile will return normally but assertTypeError will throw a TestFailedException.

Helper instance used by code generated by macro assertion.

Assume that a boolean condition, described in String message, is true. If the condition is true, this method returns normally. Else, it throws TestCanceledException with a helpful error message appended with String obtained by invoking toString on the specified clue as the exception's detail message.

This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:

• assume(a == b, "a good clue")
• assume(a != b, "a good clue")
• assume(a === b, "a good clue")
• assume(a !== b, "a good clue")
• assume(a > b, "a good clue")
• assume(a >= b, "a good clue")
• assume(a < b, "a good clue")
• assume(a <= b, "a good clue")
• assume(a startsWith "prefix", "a good clue")
• assume(a endsWith "postfix", "a good clue")
• assume(a contains "something", "a good clue")
• assume(a eq b, "a good clue")
• assume(a ne b, "a good clue")
• assume(a > 0 && b > 5, "a good clue")
• assume(a > 0 || b > 5, "a good clue")
• assume(a.isEmpty, "a good clue")
• assume(!a.isEmpty, "a good clue")
• assume(a.isInstanceOf[String], "a good clue")
• assume(a.length == 8, "a good clue")
• assume(a.size == 8, "a good clue")
• assume(a.exists(_ == 8), "a good clue")

At this time, any other form of expression will just get a TestCanceledException with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the === that returns Boolean, not Option[String] to be the default in tests. This makes === consistent between tests and production code. If you have pre-existing code you wrote under ScalaTest 1.x, in which you are expecting=== to return an Option[String], use can get that behavior back by mixing in trait LegacyTripleEquals.

Assume that a boolean condition is true. If the condition is true, this method returns normally. Else, it throws TestCanceledException.

This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:

• assume(a == b)
• assume(a != b)
• assume(a === b)
• assume(a !== b)
• assume(a > b)
• assume(a >= b)
• assume(a < b)
• assume(a <= b)
• assume(a startsWith "prefix")
• assume(a endsWith "postfix")
• assume(a contains "something")
• assume(a eq b)
• assume(a ne b)
• assume(a > 0 && b > 5)
• assume(a > 0 || b > 5)
• assume(a.isEmpty)
• assume(!a.isEmpty)
• assume(a.isInstanceOf[String])
• assume(a.length == 8)
• assume(a.size == 8)
• assume(a.exists(_ == 8))

At this time, any other form of expression will just get a TestCanceledException with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the === that returns Boolean, not Option[String] to be the default in tests. This makes === consistent between tests and production code. If you have pre-existing code you wrote under ScalaTest 1.x, in which you are expecting=== to return an Option[String], use can get that behavior back by mixing in trait LegacyTripleEquals.

This method enables the following syntax for String:

atLeast(1, str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

atLeast(1, jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

atLeast(1, xs) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

List(1, 2, 3) should contain (atLeastOneOf(1, 2))
                              ^

This method enables the following syntax for String:

atMost(3, str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

atMost(3, jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

atMost(3, xs) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

List(1, 2, 3) should contain (atMostOneOf(1, 2))
                              ^

This field enables syntax such as the following:

obj should (be theSameInstanceAs (string) and be theSameInstanceAs (string))
            ^

This method enables the following syntax for String:

between(1, 3, str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

between(1, 3, jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

between(1, 3, xs) should fullymatch regex ("Hel*o world".r)
^

Throws TestCanceledException, with the passed Throwable cause, to indicate a test failed. The getMessage method of the thrown TestCanceledException will return cause.toString.

Throws TestCanceledException, with the passed String message as the exception's detail message and Throwable cause, to indicate a test failed.

Throws TestCanceledException, with the passed String message as the exception's detail message, to indicate a test was canceled.

Throws TestCanceledException to indicate a test was canceled.

This field enables the following syntax:

"val a: String = 1" shouldNot compile
                              ^

This field enables syntax such as the following:

list should (contain ('a') and have length (7))
             ^

Provides a Constraint[A, B] class for any two types A and B, enforcing the type constraint that B is implicitly convertible to A, given an implicit Equivalence[A].

The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

This method is overridden and made implicit by subtraits ConversionCheckedTripleEquals) and ConversionCheckedLegacyTripleEquals, and overriden as non-implicit by the other subtraits in this package.

Provides a Constraint[A, B] for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an explicit Equivalence[B].

This method is used to enable the Explicitly DSL for TypeCheckedTripleEquals by requiring an explicit Equivalance[B], but taking an implicit function that provides evidence that A is a subtype of B.

The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s areEquivalent method to determine equality.

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.

Provides a Constraint[A, B] class for any two types A and B, enforcing the type constraint that A is implicitly convertible to B, given an explicit Equivalence[B].

This method is used to enable the Explicitly DSL for ConversionCheckedTripleEquals by requiring an explicit Equivalance[B], but taking an implicit function that converts from A to B.

The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s areEquivalent method to determine equality.

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.

Provides a Constraint[A, B] for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an explicit Equivalence[A].

This method is used to enable the Explicitly DSL for TypeCheckedTripleEquals by requiring an explicit Equivalance[B], but taking an implicit function that provides evidence that A is a subtype of B. For example, under TypeCheckedTripleEquals, this method (as an implicit method), would be used to compile this statement:

def closeEnoughTo1(num: Double): Boolean =
  (num === 1.0)(decided by forgivingEquality)

The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

This method is overridden and made implicit by subtraits TypeCheckedTripleEquals) and TypeCheckedLegacyTripleEquals, and overriden as non-implicit by the other subtraits in this package.

Provides a Constraint[A, B] class for any two types A and B, enforcing the type constraint that B is implicitly convertible to A, given an explicit Equivalence[A].

This method is used to enable the Explicitly DSL for ConversionCheckedTripleEquals by requiring an explicit Equivalance[A], but taking an implicit function that converts from B to A. For example, under ConversionCheckedTripleEquals, this method (as an implicit method), would be used to compile this statement:

def closeEnoughTo1(num: Double): Boolean =
  (num === 1.0)(decided by forgivingEquality)

The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

This method is overridden and made implicit by subtraits ConversionCheckedTripleEquals) and ConversionCheckedLegacyTripleEquals, and overriden as non-implicit by the other subtraits in this package.

Implicitly converts an object of a Numeric type to a PlusOrMinusWrapper, to enable a +- method to be invoked on that object.

This implicit conversion method converts a Symbol to a HavePropertyMatcherGenerator, to enable the symbol to be used with the have ('author ("Dickens")) syntax.

Implicitly converts an object of type T to a AnyShouldWrapper[T], to enable should methods to be invokable on that object.

Converts 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.

Converts 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.

Converts 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.

Converts 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.

Implicitly converts an object of type scala.util.matching.Regex to a RegexWrapper, to enable withGroup and withGroups methods to be invokable on that object.

Implicitly converts an object of type java.lang.String to a StringShouldWrapper, to enable should methods to be invokable on that object.

This field enables syntax such as the following:

result should equal ("hello") (decided by defaultEquality)
                               ^

Returns an Equality[A] for any type A that determines equality by first calling .deep on any Array (on either the left or right side), then comparing the resulting objects with ==.

This field enables the following syntax:

seq should be (defined)
              ^

This method enables the following syntax:

list should (not be definedAt (7) and not be definedAt (9))
                    ^

This field enables syntax such as the following, given an Equivalence[String] named myStringEquivalence:

result should equal ("hello") (determined by myStringEquivalence)
                               ^

This field enables the following syntax:

list should be (empty)
                ^

This field enables syntax such as the following:

string should (endWith ("ago") and include ("score"))
               ^

This method enables syntax such as the following:

result should equal (null)
              ^

This method enables syntax such as the following:

result should equal (100 +- 1)
              ^

This method enables the following syntax:

result should equal (7)
              ^

The left should equal (right) syntax works by calling == on the left value, passing in the right value, on every type except arrays. If both left and right are arrays, deep will be invoked on both left and right before comparing them with ==. Thus, even though this expression will yield false, because Array's equals method compares object identity:

Array(1, 2) == Array(1, 2) // yields false

The following expression will not result in a TestFailedException, because ScalaTest will compare the two arrays structurally, taking into consideration the equality of the array's contents:

Array(1, 2) should equal (Array(1, 2)) // succeeds (i.e., does not throw TestFailedException)

If you ever do want to verify that two arrays are actually the same object (have the same identity), you can use the be theSameInstanceAs syntax.

This method enables the following syntax for String:

every(str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

every(jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

every(xs) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for String:

exactly(str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

exactly(jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

exactly(xs) should fullymatch regex ("Hel*o world".r)
^

This field enables the following syntax:

file should exist
            ^

Throws TestFailedException, with the passed Throwable cause, to indicate a test failed. The getMessage method of the thrown TestFailedException will return cause.toString.

Throws TestFailedException, with the passed String message as the exception's detail message and Throwable cause, to indicate a test failed.

Throws TestFailedException, with the passed String message as the exception's detail message, to indicate a test failed.

Throws TestFailedException to indicate a test failed.

This field enables syntax such as the following:

string should (fullyMatch regex ("Hel*o, wor.d") and not have length (99))
               ^

This field enables syntax such as the following:

list should (have length (3) and not contain ('a'))
             ^

This method enables the following syntax:

List(1, 2, 3) should contain (inOrder(1, 2))
                              ^

This method enables the following syntax:

List(1, 2, 3) should contain (inOrderOnly(1, 2))
                              ^

This field enables syntax such as the following:

string should (include ("hope") and not startWith ("no"))
               ^

Intercept and return an exception that's expected to be thrown by the passed function value. The thrown exception must be an instance of the type specified by the type parameter of this method. This method invokes the passed function. If the function throws an exception that's an instance of the specified type, this method returns that exception. Else, whether the passed function returns normally or completes abruptly with a different exception, this method throws TestFailedException.

Note that the type specified as this method's type parameter may represent any subtype of AnyRef, not just Throwable or one of its subclasses. In Scala, exceptions can be caught based on traits they implement, so it may at times make sense to specify a trait that the intercepted exception's class must mix in. If a class instance is passed for a type that could not possibly be used to catch an exception (such as String, for example), this method will complete abruptly with a TestFailedException.

This field enables the following syntax:

map should not contain key (10)
                       ^

This field enables the following syntax:

"hi" should not have length (3)
                     ^

Provides a Constraint[A, B] class for any two types A and B, enforcing the type constraint that A is implicitly convertible to B, given an implicit Equivalence[B].

The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s areEquivalent method to determine equality.

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.

Provides a Constraint[A, B] for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an implicit Equivalence[B].

The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

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.

This field enables the following syntax:

result should matchPattern { case Person("Bob", _) => }
              ^

This method enables the following syntax:

exception should not have message ("file not found")
                          ^

This method enables the following syntax for String:

no(str) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax for java.util.Map:

no(jmap) should fullymatch regex ("Hel*o world".r)
^

This method enables the following syntax:

no(xs) should fullymatch regex ("Hel*o world".r)
^

This field enables the following syntax:

noException should be thrownBy
^

This method enables the following syntax:

List(1, 2, 3) should contain (noneOf(1, 2))
                              ^

This field enables syntax like the following:

myFile should (not be an (directory) and not have ('name ("foo.bar")))
               ^

This method enables syntax such as the following:

book should have (message ("A TALE OF TWO CITIES") (of [Book]), title ("A Tale of Two Cities"))
                                                    ^

This method enables the following syntax:

List(1, 2, 3) should contain (oneOf(1, 2))
                              ^

This method enables the following syntax:

List(1, 2, 3) should contain (only(1, 2))
                              ^

This method enables the following syntax:

evaluating { "hi".charAt(-1) } should produce [StringIndexOutOfBoundsException]
                                      ^

This field enables the following syntax:

file should be (readable)
                ^

This field enables the following syntax:

"eight" should not fullyMatch regex ("""(-)?(\d+)(\.\d*)?""".r)
                              ^

This field enables the following syntax:

set should not have size (3)
                    ^

This field enables the following syntax:

seq should be (sorted)
              ^

This field enables syntax such as the following:

string should (startWith ("Four") and include ("year"))
               ^

This method enables the following syntax:

the [FileNotFoundException] should be thrownBy { ... }
^

This method enables the following syntax:

List(1, 2, 3) should contain (theSameElementsAs(List(1, 2, 3)))
                              ^

This method enables the following syntax:

List(1, 2, 3) should contain (theSameElementsInOrderAs(List(1, 2)))
                              ^

This field enables the following syntax:

oneString should not be theSameInstanceAs (anotherString)
                        ^

This method enables the following syntax:

a [RuntimeException] should be thrownBy {...}
                               ^

Trap and return any thrown exception that would normally cause a ScalaTest test to fail, or create and return a new RuntimeException indicating no exception is thrown.

This method is intended to be used in the Scala interpreter to eliminate large stack traces when trying out ScalaTest assertions and matcher expressions. It is not intended to be used in regular test code. If you want to ensure that a bit of code throws an expected exception, use intercept, not trap. Here's an example interpreter session without trap:

scala> import org.scalatest._
import org.scalatest._
scala> import Matchers._
import Matchers._
scala> val x = 12
a: Int = 12
scala> x shouldEqual 13
org.scalatest.exceptions.TestFailedException: 12 did not equal 13
   at org.scalatest.Assertions$class.newAssertionFailedException(Assertions.scala:449)
   at org.scalatest.Assertions$.newAssertionFailedException(Assertions.scala:1203)
   at org.scalatest.Assertions$AssertionsHelper.macroAssertTrue(Assertions.scala:417)
   at .<init>(<console>:15)
   at .<clinit>(<console>)
   at .<init>(<console>:7)
   at .<clinit>(<console>)
   at $print(<console>)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:597)
   at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:731)
   at scala.tools.nsc.interpreter.IMain$Request.loadAndRun(IMain.scala:980)
   at scala.tools.nsc.interpreter.IMain.loadAndRunReq$1(IMain.scala:570)
   at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:601)
   at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:565)
   at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:745)
   at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:790)
   at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:702)
   at scala.tools.nsc.interpreter.ILoop.processLine$1(ILoop.scala:566)
   at scala.tools.nsc.interpreter.ILoop.innerLoop$1(ILoop.scala:573)
   at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:576)
   at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:867)
   at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:822)
   at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:822)
   at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
   at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:822)
   at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:83)
   at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:96)
   at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:105)
   at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)

That's a pretty tall stack trace. Here's what it looks like when you use trap:

scala> trap { x shouldEqual 13 }
res1: Throwable = org.scalatest.exceptions.TestFailedException: 12 did not equal 13

Much less clutter. Bear in mind, however, that if no exception is thrown by the passed block of code, the trap method will create a new NormalResult (a subclass of Throwable made for this purpose only) and return that. If the result was the Unit value, it will simply say that no exception was thrown:

scala> trap { x shouldEqual 12 }
res2: Throwable = No exception was thrown.

If the passed block of code results in a value other than Unit, the NormalResult's toString will print the value:

scala> trap { "Dude!" }
res3: Throwable = No exception was thrown. Instead, result was: "Dude!"

Although you can access the result value from the NormalResult, its type is Any and therefore not very convenient to use. It is not intended that trap be used in test code. The sole intended use case for trap is decluttering Scala interpreter sessions by eliminating stack traces when executing assertion and matcher expressions.

This field enables the following syntax:

"val a: String = 1" shouldNot typeCheck
                              ^

Provides a Constraint[A, B] for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an implicit Equivalence[A].

The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

This method is overridden and made implicit by subtraits TypeCheckedTripleEquals) and TypeCheckedLegacyTripleEquals, and overriden as non-implicit by the other subtraits in this package.

Provides a Constraint[A, B] class for any two types A and B, with no type constraint enforced, given an implicit Equality[A].

The returned Constraint's areEqual method uses the implicitly passed Equality[A]'s areEqual method to determine equality.

This method is overridden and made implicit by subtraits TripleEquals and LegacyTripleEquals, and overriden as non-implicit by the other subtraits in this package.

This field enables the following syntax:

map should not contain value (10)
                       ^

Executes the block of code passed as the second parameter, and, if it completes abruptly with a ModifiableMessage exception, prepends the "clue" string passed as the first parameter to the beginning of the detail message of that thrown exception, then rethrows it. If clue does not end in a white space character, one space will be added between it and the existing detail message (unless the detail message is not defined).

This method allows you to add more information about what went wrong that will be reported when a test fails. Here's an example:

withClue("(Employee's name was: " + employee.name + ")") {
  intercept[IllegalArgumentException] {
    employee.getTask(-1)
  }
}

If an invocation of intercept completed abruptly with an exception, the resulting message would be something like:

(Employee's name was Bob Jones) Expected IllegalArgumentException to be thrown, but no exception was thrown

This field enables the following syntax:

file should be (writable)
                ^

Assert that an Option[String] is None. If the condition is None, this method returns normally. Else, it throws TestFailedException with the String value of the Some included in the TestFailedException's detail message.

This form of assert is usually called in conjunction with an implicit conversion to Equalizer, using a === comparison, as in:

assert(a === b)

For more information on how this mechanism works, see the documentation for Equalizer.

Assert that an Option[String] is None. If the condition is None, this method returns normally. Else, it throws TestFailedException with the String value of the Some, as well as the String obtained by invoking toString on the specified clue, included in the TestFailedException's detail message.

This form of assert is usually called in conjunction with an implicit conversion to Equalizer, using a === comparison, as in:

assert(a === b, "extra info reported if assertion fails")

For more information on how this mechanism works, see the documentation for Equalizer.

Assume that an Option[String] is None. If the condition is None, this method returns normally. Else, it throws TestCanceledException with the String value of the Some included in the TestCanceledException's detail message.

This form of assume is usually called in conjunction with an implicit conversion to Equalizer, using a === comparison, as in:

assume(a === b)

For more information on how this mechanism works, see the documentation for Equalizer.

Assume that an Option[String] is None. If the condition is None, this method returns normally. Else, it throws TestCanceledException with the String value of the Some, as well as the String obtained by invoking toString on the specified clue, included in the TestCanceledException's detail message.

This form of assume is usually called in conjunction with an implicit conversion to Equalizer, using a === comparison, as in:

assume(a === b, "extra info reported if assertion fails")

For more information on how this mechanism works, see the documentation for Equalizer.

The evaluating { ... } should produce [...Exception] syntax has been deprecated and will be removed in a future version of ScalaTest. Please use a/an [...Exception] should be thrownBy { ... } instead.

This method enables syntax such as the following:

evaluating { "hi".charAt(-1) } should produce [StringIndexOutOfBoundsException]
^

This expect method has been deprecated; Please use assertResult instead.

To get rid of the deprecation warning, simply replace expect with assertResult. The name expect will be used for a different purposes in a future version of ScalaTest.

This expect method has been deprecated; Please use assertResult instead.

To get rid of the deprecation warning, simply replace expect with assertResult. The name expect will be used for a different purposes in a future version of ScalaTest.

This expectResult method has been deprecated; Please use assertResult instead.

To get rid of the deprecation warning, simply replace expectResult with assertResult. The name expectResult will be used for a different purposes in a future version of ScalaTest.

This expectResult method has been deprecated; Please use assertResult instead.

To get rid of the deprecation warning, simply replace expectResult with assertResult. The name expectResult will be used for a different purposes in a future version of ScalaTest.