gomega

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 Go to latest Published: Jun 6, 2015 License: MIT, Apache-2.0 Imports: 8 Imported by: 0

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Jump straight to the docs to learn about Gomega, including a list of all available matchers.

To discuss Gomega and get updates, join the google group.

Ginkgo: a BDD Testing Framework for Golang

Learn more about Ginkgo here

License

Gomega is MIT-Licensed

The ConsistOf matcher uses goraph which is embedded in the source to simplify distribution. goraph has an MIT license.

Documentation

Overview

Gomega is the Ginkgo BDD-style testing framework's preferred matcher library.

The godoc documentation describes Gomega's API. More comprehensive documentation (with examples!) is available at http://onsi.github.io/gomega/

Gomega on Github: http://github.com/onsi/gomega

Learn more about Ginkgo online: http://onsi.github.io/ginkgo

Ginkgo on Github: http://github.com/onsi/ginkgo

Gomega is MIT-Licensed

Index

Constants

View Source 
const GOMEGA_VERSION = "1.0"

Variables

This section is empty.

Functions

func BeADirectory added in v0.0.32 

func BeADirectory() types.GomegaMatcher

BeADirectory succeeds iff a file exists and is a directory. Actual must be a string representing the abs path to the file being checked.

func BeARegularFile added in v0.0.32 

func BeARegularFile() types.GomegaMatcher

BeARegularFile succeeds iff a file exists and is a regular file. Actual must be a string representing the abs path to the file being checked.

func BeAnExistingFile added in v0.0.32 

func BeAnExistingFile() types.GomegaMatcher

BeAnExistingFile succeeds if a file exists. Actual must be a string representing the abs path to the file being checked.

func BeAssignableToTypeOf 

func BeAssignableToTypeOf(expected interface{}) types.GomegaMatcher

BeAssignableToTypeOf succeeds if actual is assignable to the type of expected. It will return an error when one of the values is nil. 

	  Ω(0).Should(BeAssignableToTypeOf(0))         // Same values
	  Ω(5).Should(BeAssignableToTypeOf(-1))        // different values same type
	  Ω("foo").Should(BeAssignableToTypeOf("bar")) // different values same type
   Ω(struct{ Foo string }{}).Should(BeAssignableToTypeOf(struct{ Foo string }{}))

func BeClosed 

func BeClosed() types.GomegaMatcher

BeClosed succeeds if actual is a closed channel. It is an error to pass a non-channel to BeClosed, it is also an error to pass nil

In order to check whether or not the channel is closed, Gomega must try to read from the channel (even in the `ShouldNot(BeClosed())` case). You should keep this in mind if you wish to make subsequent assertions about values coming down the channel.

Also, if you are testing that a *buffered* channel is closed you must first read all values out of the channel before asserting that it is closed (it is not possible to detect that a buffered-channel has been closed until all its buffered values are read).

Finally, as a corollary: it is an error to check whether or not a send-only channel is closed.

func BeEmpty 

func BeEmpty() types.GomegaMatcher

BeEmpty succeeds if actual is empty. Actual must be of type string, array, map, chan, or slice.

func BeEquivalentTo 

func BeEquivalentTo(expected interface{}) types.GomegaMatcher

BeEquivalentTo is more lax than Equal, allowing equality between different types. This is done by converting actual to have the type of expected before attempting equality with reflect.DeepEqual. It is an error for actual and expected to be nil. Use BeNil() instead.

func BeFalse 

func BeFalse() types.GomegaMatcher

BeFalse succeeds if actual is false

func BeNil 

func BeNil() types.GomegaMatcher

BeNil succeeds if actual is nil

func BeNumerically 

func BeNumerically(comparator string, compareTo ...interface{}) types.GomegaMatcher

BeNumerically performs numerical assertions in a type-agnostic way. Actual and expected should be numbers, though the specific type of number is irrelevant (floa32, float64, uint8, etc...).

There are six, self-explanatory, supported comparators: 

Ω(1.0).Should(BeNumerically("==", 1))
Ω(1.0).Should(BeNumerically("~", 0.999, 0.01))
Ω(1.0).Should(BeNumerically(">", 0.9))
Ω(1.0).Should(BeNumerically(">=", 1.0))
Ω(1.0).Should(BeNumerically("<", 3))
Ω(1.0).Should(BeNumerically("<=", 1.0))

func BeSent 

func BeSent(arg interface{}) types.GomegaMatcher

BeSent succeeds if a value can be sent to actual. Actual must be a channel (and cannot be a receive-only channel) that can sent the type of the value passed into BeSent -- anything else is an error. In addition, actual must not be closed.

BeSent never blocks:

- If the channel `c` is not ready to receive then Ω(c).Should(BeSent("foo")) will fail immediately - If the channel `c` is eventually ready to receive then Eventually(c).Should(BeSent("foo")) will succeed.. presuming the channel becomes ready to receive before Eventually's timeout - If the channel `c` is closed then Ω(c).Should(BeSent("foo")) and Ω(c).ShouldNot(BeSent("foo")) will both fail immediately

Of course, the value is actually sent to the channel. The point of `BeSent` is less to make an assertion about the availability of the channel (which is typically an implementation detail that your test should not be concerned with). Rather, the point of `BeSent` is to make it possible to easily and expressively write tests that can timeout on blocked channel sends.

func BeTemporally 

func BeTemporally(comparator string, compareTo time.Time, threshold ...time.Duration) types.GomegaMatcher

BeTemporally compares time.Time's like BeNumerically Actual and expected must be time.Time. The comparators are the same as for BeNumerically 

Ω(time.Now()).Should(BeTemporally(">", time.Time{}))
Ω(time.Now()).Should(BeTemporally("~", time.Now(), time.Second))

func BeTrue 

func BeTrue() types.GomegaMatcher

BeTrue succeeds if actual is true

func BeZero 

func BeZero() types.GomegaMatcher

BeZero succeeds if actual is the zero value for its type or if actual is nil.

func ConsistOf 

func ConsistOf(elements ...interface{}) types.GomegaMatcher

ConsistOf succeeds if actual contains preciely the elements passed into the matcher. The ordering of the elements does not matter. By default ConsistOf() uses Equal() to match the elements, however custom matchers can be passed in instead. Here are some examples: 

Ω([]string{"Foo", "FooBar"}).Should(ConsistOf("FooBar", "Foo"))
Ω([]string{"Foo", "FooBar"}).Should(ConsistOf(ContainSubstring("Bar"), "Foo"))
Ω([]string{"Foo", "FooBar"}).Should(ConsistOf(ContainSubstring("Foo"), ContainSubstring("Foo")))

Actual must be an array, slice or map. For maps, ConsistOf matches against the map's values.

You typically pass variadic arguments to ConsistOf (as in the examples above). However, if you need to pass in a slice you can provided that it is the only element passed in to ConsistOf: 

Ω([]string{"Foo", "FooBar"}).Should(ConsistOf([]string{"FooBar", "Foo"}))

Note that Go's type system does not allow you to write this as ConsistOf([]string{"FooBar", "Foo"}...) as []string and []interface{} are different types - hence the need for this special rule.

func ContainElement 

func ContainElement(element interface{}) types.GomegaMatcher

ContainElement succeeds if actual contains the passed in element. By default ContainElement() uses Equal() to perform the match, however a matcher can be passed in instead: 

Ω([]string{"Foo", "FooBar"}).Should(ContainElement(ContainSubstring("Bar")))

Actual must be an array, slice or map. For maps, ContainElement searches through the map's values.

func ContainSubstring 

func ContainSubstring(substr string, args ...interface{}) types.GomegaMatcher

ContainSubstring succeeds if actual is a string or stringer that contains the passed-in regexp. Optional arguments can be provided to construct the substring via fmt.Sprintf().

func Equal 

func Equal(expected interface{}) types.GomegaMatcher

Equal uses reflect.DeepEqual to compare actual with expected. Equal is strict about types when performing comparisons. It is an error for both actual and expected to be nil. Use BeNil() instead.

func HaveKey 

func HaveKey(key interface{}) types.GomegaMatcher

HaveKey succeeds if actual is a map with the passed in key. By default HaveKey uses Equal() to perform the match, however a matcher can be passed in instead: 

Ω(map[string]string{"Foo": "Bar", "BazFoo": "Duck"}).Should(HaveKey(MatchRegexp(`.+Foo$`)))

func HaveKeyWithValue 

func HaveKeyWithValue(key interface{}, value interface{}) types.GomegaMatcher

HaveKeyWithValue succeeds if actual is a map with the passed in key and value. By default HaveKeyWithValue uses Equal() to perform the match, however a matcher can be passed in instead: 

Ω(map[string]string{"Foo": "Bar", "BazFoo": "Duck"}).Should(HaveKeyWithValue("Foo", "Bar"))
Ω(map[string]string{"Foo": "Bar", "BazFoo": "Duck"}).Should(HaveKeyWithValue(MatchRegexp(`.+Foo$`), "Bar"))

func HaveLen 

func HaveLen(count int) types.GomegaMatcher

HaveLen succeeds if actual has the passed-in length. Actual must be of type string, array, map, chan, or slice.

func HaveOccurred 

func HaveOccurred() types.GomegaMatcher

HaveOccurred succeeds if actual is a non-nil error The typical Go error checking pattern looks like: 

err := SomethingThatMightFail()
Ω(err).ShouldNot(HaveOccurred())

func HavePrefix added in v0.0.32 

func HavePrefix(prefix string, args ...interface{}) types.GomegaMatcher

HavePrefix succeeds if actual is a string or stringer that contains the passed-in string as a prefix. Optional arguments can be provided to construct via fmt.Sprintf().

func HaveSuffix added in v0.0.32 

func HaveSuffix(suffix string, args ...interface{}) types.GomegaMatcher

HaveSuffix succeeds if actual is a string or stringer that contains the passed-in string as a suffix. Optional arguments can be provided to construct via fmt.Sprintf().

func InterceptGomegaFailures 

func InterceptGomegaFailures(f func()) []string

InterceptGomegaHandlers runs a given callback and returns an array of failure messages generated by any Gomega assertions within the callback.

This is accomplished by temporarily replacing the *global* fail handler with a fail handler that simply annotates failures. The original fail handler is reset when InterceptGomegaFailures returns.

This is most useful when testing custom matchers, but can also be used to check on a value using a Gomega assertion without causing a test failure.

func MatchError 

func MatchError(expected interface{}) types.GomegaMatcher

MatchError succeeds if actual is a non-nil error that matches the passed in string/error.

These are valid use-cases: 

Ω(err).Should(MatchError("an error")) //asserts that err.Error() == "an error"
Ω(err).Should(MatchError(SomeError)) //asserts that err == SomeError (via reflect.DeepEqual)

It is an error for err to be nil or an object that does not implement the Error interface

func MatchJSON 

func MatchJSON(json interface{}) types.GomegaMatcher

MatchJSON succeeds if actual is a string or stringer of JSON that matches the expected JSON. The JSONs are decoded and the resulting objects are compared via reflect.DeepEqual so things like key-ordering and whitespace shouldn't matter.

func MatchRegexp 

func MatchRegexp(regexp string, args ...interface{}) types.GomegaMatcher

MatchRegexp succeeds if actual is a string or stringer that matches the passed-in regexp. Optional arguments can be provided to construct a regexp via fmt.Sprintf().

func Panic 

func Panic() types.GomegaMatcher

Panic succeeds if actual is a function that, when invoked, panics. Actual must be a function that takes no arguments and returns no results.

func Receive 

func Receive(args ...interface{}) types.GomegaMatcher

Receive succeeds if there is a value to be received on actual. Actual must be a channel (and cannot be a send-only channel) -- anything else is an error.

Receive returns immediately and never blocks:

- If there is nothing on the channel `c` then Ω(c).Should(Receive()) will fail and Ω(c).ShouldNot(Receive()) will pass.

- If the channel `c` is closed then Ω(c).Should(Receive()) will fail and Ω(c).ShouldNot(Receive()) will pass.

- If there is something on the channel `c` ready to be read, then Ω(c).Should(Receive()) will pass and Ω(c).ShouldNot(Receive()) will fail.

If you have a go-routine running in the background that will write to channel `c` you can: 

Eventually(c).Should(Receive())

This will timeout if nothing gets sent to `c` (you can modify the timeout interval as you normally do with `Eventually`)

A similar use-case is to assert that no go-routine writes to a channel (for a period of time). You can do this with `Consistently`: 

Consistently(c).ShouldNot(Receive())

You can pass `Receive` a matcher. If you do so, it will match the received object against the matcher. For example: 

Ω(c).Should(Receive(Equal("foo")))

When given a matcher, `Receive` will always fail if there is nothing to be received on the channel.

Passing Receive a matcher is especially useful when paired with Eventually: 

Eventually(c).Should(Receive(ContainSubstring("bar")))

will repeatedly attempt to pull values out of `c` until a value matching "bar" is received.

Finally, if you want to have a reference to the value *sent* to the channel you can pass the `Receive` matcher a pointer to a variable of the appropriate type: 

var myThing thing
Eventually(thingChan).Should(Receive(&myThing))
Ω(myThing.Sprocket).Should(Equal("foo"))
Ω(myThing.IsValid()).Should(BeTrue())

func RegisterFailHandler 

func RegisterFailHandler(handler types.GomegaFailHandler)

RegisterFailHandler connects Ginkgo to Gomega. When a matcher fails the fail handler passed into RegisterFailHandler is called.

func RegisterTestingT 

func RegisterTestingT(t types.GomegaTestingT)

RegisterTestingT connects Gomega to Golang's XUnit style Testing.T tests. You'll need to call this at the top of each XUnit style test: 

func TestFarmHasCow(t *testing.T) {
    RegisterTestingT(t)

	   f := farm.New([]string{"Cow", "Horse"})
    Expect(f.HasCow()).To(BeTrue(), "Farm should have cow")
}

Note that this *testing.T is registered *globally* by Gomega (this is why you don't have to pass `t` down to the matcher itself). This means that you cannot run the XUnit style tests in parallel as the global fail handler cannot point to more than one testing.T at a time.

(As an aside: Ginkgo gets around this limitation by running parallel tests in different *processes*).

func SetDefaultConsistentlyDuration 

func SetDefaultConsistentlyDuration(t time.Duration)

Set the default duration for Consistently. Consistently will verify that your condition is satsified for this long.

func SetDefaultConsistentlyPollingInterval 

func SetDefaultConsistentlyPollingInterval(t time.Duration)

Set the default polling interval for Consistently.

func SetDefaultEventuallyPollingInterval 

func SetDefaultEventuallyPollingInterval(t time.Duration)

Set the default polling interval for Eventually.

func SetDefaultEventuallyTimeout 

func SetDefaultEventuallyTimeout(t time.Duration)

Set the default timeout duration for Eventually. Eventually will repeatedly poll your condition until it succeeds, or until this timeout elapses.

func Succeed added in v0.0.32 

func Succeed() types.GomegaMatcher

Succeed passes if actual is a nil error Succeed is intended to be used with functions that return a single error value. Instead of 

err := SomethingThatMightFail()
Ω(err).ShouldNot(HaveOccurred())

You can write: 

Ω(SomethingThatMightFail()).Should(Succeed())

It is a mistake to use Succeed with a function that has multiple return values. Gomega's Ω and Expect functions automatically trigger failure if any return values after the first return value are non-zero/non-nil. This means that Ω(MultiReturnFunc()).ShouldNot(Succeed()) can never pass.

Types

type GomegaAssertion 

type GomegaAssertion interface {
	Should(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool
	ShouldNot(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool

	To(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool
	ToNot(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool
	NotTo(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool
}

GomegaAssertion is returned by Ω and Expect and compares the actual value to the matcher passed to the Should/ShouldNot and To/ToNot/NotTo methods.

Typically Should/ShouldNot are used with Ω and To/ToNot/NotTo are used with Expect though this is not enforced.

All methods take a variadic optionalDescription argument. This is passed on to fmt.Sprintf() and is used to annotate failure messages.

All methods return a bool that is true if hte assertion passed and false if it failed.

Example: 

Ω(farm.HasCow()).Should(BeTrue(), "Farm %v should have a cow", farm)

func Expect 

func Expect(actual interface{}, extra ...interface{}) GomegaAssertion

Expect wraps an actual value allowing assertions to be made on it: 

Expect("foo").To(Equal("foo"))

If Expect is passed more than one argument it will pass the *first* argument to the matcher. All subsequent arguments will be required to be nil/zero.

This is convenient if you want to make an assertion on a method/function that returns a value and an error - a common patter in Go.

For example, given a function with signature: 

func MyAmazingThing() (int, error)

Then: 

Expect(MyAmazingThing()).Should(Equal(3))

Will succeed only if `MyAmazingThing()` returns `(3, nil)`

Expect and Ω are identical

func ExpectWithOffset 

func ExpectWithOffset(offset int, actual interface{}, extra ...interface{}) GomegaAssertion

ExpectWithOffset wraps an actual value allowing assertions to be made on it: 

ExpectWithOffset(1, "foo").To(Equal("foo"))

Unlike `Expect` and `Ω`, `ExpectWithOffset` takes an additional integer argument this is used to modify the call-stack offset when computing line numbers.

This is most useful in helper functions that make assertions. If you want Gomega's error message to refer to the calling line in the test (as opposed to the line in the helper function) set the first argument of `ExpectWithOffset` appropriately.

func Ω 

func Ω(actual interface{}, extra ...interface{}) GomegaAssertion

Ω wraps an actual value allowing assertions to be made on it: 

Ω("foo").Should(Equal("foo"))

If Ω is passed more than one argument it will pass the *first* argument to the matcher. All subsequent arguments will be required to be nil/zero.

This is convenient if you want to make an assertion on a method/function that returns a value and an error - a common patter in Go.

For example, given a function with signature: 

func MyAmazingThing() (int, error)

Then: 

Ω(MyAmazingThing()).Should(Equal(3))

Will succeed only if `MyAmazingThing()` returns `(3, nil)`

Ω and Expect are identical

type GomegaAsyncAssertion 

type GomegaAsyncAssertion interface {
	Should(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool
	ShouldNot(matcher types.GomegaMatcher, optionalDescription ...interface{}) bool
}

GomegaAsyncAssertion is returned by Eventually and Consistently and polls the actual value passed into Eventually against the matcher passed to the Should and ShouldNot methods.

Both Should and ShouldNot take a variadic optionalDescription argument. This is passed on to fmt.Sprintf() and is used to annotate failure messages. This allows you to make your failure messages more descriptive

Both Should and ShouldNot return a boolean that is true if the assertion passed and false if it failed.

Example: 

Eventually(myChannel).Should(Receive(), "Something should have come down the pipe.")
Consistently(myChannel).ShouldNot(Receive(), "Nothing should have come down the pipe.")

func Consistently 

func Consistently(actual interface{}, intervals ...interface{}) GomegaAsyncAssertion

Consistently wraps an actual value allowing assertions to be made on it. The assertion is tried periodically and is required to pass for a period of time.

Both the total time and polling interval are configurable as optional arguments: The first optional argument is the duration that Consistently will run for The second optional argument is the polling interval

Both intervals can either be specified as time.Duration, parsable duration strings or as floats/integers. In the last case they are interpreted as seconds.

If Consistently is passed an actual that is a function taking no arguments and returning at least one value, then Consistently will call the function periodically and try the matcher against the function's first return value.

If the function returns more than one value, then Consistently will pass the first value to the matcher and assert that all other values are nil/zero. This allows you to pass Consistently a function that returns a value and an error - a common pattern in Go.

Consistently is useful in cases where you want to assert that something *does not happen* over a period of tiem. For example, you want to assert that a goroutine does *not* send data down a channel. In this case, you could: 

Consistently(channel).ShouldNot(Receive())

Consistently's default duration is 100ms, and its default polling interval is 10ms

func ConsistentlyWithOffset 

func ConsistentlyWithOffset(offset int, actual interface{}, intervals ...interface{}) GomegaAsyncAssertion

ConsistentlyWithOffset operates like Consistnetly but takes an additional initial argument to indicate an offset in the call stack. This is useful when building helper functions that contain matchers. To learn more, read about `ExpectWithOffset`.

func Eventually 

func Eventually(actual interface{}, intervals ...interface{}) GomegaAsyncAssertion

Eventually wraps an actual value allowing assertions to be made on it. The assertion is tried periodically until it passes or a timeout occurs.

Both the timeout and polling interval are configurable as optional arguments: The first optional argument is the timeout The second optional argument is the polling interval

Both intervals can either be specified as time.Duration, parsable duration strings or as floats/integers. In the last case they are interpreted as seconds.

If Eventually is passed an actual that is a function taking no arguments and returning at least one value, then Eventually will call the function periodically and try the matcher against the function's first return value.

Example: 

Eventually(func() int {
    return thingImPolling.Count()
}).Should(BeNumerically(">=", 17))

Note that this example could be rewritten: 

Eventually(thingImPolling.Count).Should(BeNumerically(">=", 17))

If the function returns more than one value, then Eventually will pass the first value to the matcher and assert that all other values are nil/zero. This allows you to pass Eventually a function that returns a value and an error - a common pattern in Go.

For example, consider a method that returns a value and an error: 

func FetchFromDB() (string, error)

Then 

Eventually(FetchFromDB).Should(Equal("hasselhoff"))

Will pass only if the the returned error is nil and the returned string passes the matcher.

Eventually's default timeout is 1 second, and its default polling interval is 10ms

func EventuallyWithOffset 

func EventuallyWithOffset(offset int, actual interface{}, intervals ...interface{}) GomegaAsyncAssertion

EventuallyWithOffset operates like Eventually but takes an additional initial argument to indicate an offset in the call stack. This is useful when building helper functions that contain matchers. To learn more, read about `ExpectWithOffset`.

type OmegaMatcher 

type OmegaMatcher types.GomegaMatcher

OmegaMatcher is deprecated in favor of the better-named and better-organized types.GomegaMatcher but sticks around to support existing code that uses it

Source Files

View all Source files

Directories

Path Synopsis
Gomega's format package pretty-prints objects.
 Gomega's format package pretty-prints objects.
Package gbytes provides a buffer that supports incrementally detecting input.
 Package gbytes provides a buffer that supports incrementally detecting input.
Package gexec provides support for testing external processes.
 Package gexec provides support for testing external processes.
Package ghttp supports testing HTTP clients by providing a test server (simply a thin wrapper around httptest's server) that supports registering multiple handlers.
 Package ghttp supports testing HTTP clients by providing a test server (simply a thin wrapper around httptest's server) that supports registering multiple handlers.
internal
assertion
asyncassertion
fakematcher
testingtsupport
Gomega matchers This package implements the Gomega matchers and does not typically need to be imported.
 Gomega matchers This package implements the Gomega matchers and does not typically need to be imported.
support/goraph/bipartitegraph
support/goraph/edge
support/goraph/node
support/goraph/util

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