Documentation

Overview

    Package gbytes provides a buffer that supports incrementally detecting input.

    You use gbytes.Buffer with the gbytes.Say matcher. When Say finds a match, it fastforwards the buffer's read cursor to the end of that match.

    Subsequent matches against the buffer will only operate against data that appears *after* the read cursor.

    The read cursor is an opaque implementation detail that you cannot access. You should use the Say matcher to sift through the buffer. You can always access the entire buffer's contents with Contents().

    Index

    Constants

    This section is empty.

    Variables

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    var ErrTimeout = errors.New("timeout occurred")

      ErrTimeout is returned by TimeoutCloser, TimeoutReader, and TimeoutWriter when the underlying Closer/Reader/Writer does not return within the specified timeout

      Functions

      func Say

      func Say(expected string, args ...interface{}) *sayMatcher

        Say is a Gomega matcher that operates on gbytes.Buffers:

        Expect(buffer).Should(Say("something"))
        

        will succeed if the unread portion of the buffer matches the regular expression "something".

        When Say succeeds, it fast forwards the gbytes.Buffer's read cursor to just after the succesful match. Thus, subsequent calls to Say will only match against the unread portion of the buffer

        Say pairs very well with Eventually. To assert that a buffer eventually receives data matching "[123]-star" within 3 seconds you can:

        Eventually(buffer, 3).Should(Say("[123]-star"))
        

        Ditto with consistently. To assert that a buffer does not receive data matching "never-see-this" for 1 second you can:

        Consistently(buffer, 1).ShouldNot(Say("never-see-this"))
        

        In addition to bytes.Buffers, Say can operate on objects that implement the gbytes.BufferProvider interface. In such cases, Say simply operates on the *gbytes.Buffer returned by Buffer()

        If the buffer is closed, the Say matcher will tell Eventually to abort.

        func TimeoutCloser

        func TimeoutCloser(c io.Closer, timeout time.Duration) io.Closer

          TimeoutCloser returns an io.Closer that wraps the passed-in io.Closer. If the underlying Closer fails to close within the alloted timeout ErrTimeout is returned.

          func TimeoutReader

          func TimeoutReader(r io.Reader, timeout time.Duration) io.Reader

            TimeoutReader returns an io.Reader that wraps the passed-in io.Reader. If the underlying Reader fails to read within the alloted timeout ErrTimeout is returned.

            func TimeoutWriter

            func TimeoutWriter(w io.Writer, timeout time.Duration) io.Writer

              TimeoutWriter returns an io.Writer that wraps the passed-in io.Writer. If the underlying Writer fails to write within the alloted timeout ErrTimeout is returned.

              Types

              type Buffer

              type Buffer struct {
              	// contains filtered or unexported fields
              }

                gbytes.Buffer implements an io.Writer and can be used with the gbytes.Say matcher.

                You should only use a gbytes.Buffer in test code. It stores all writes in an in-memory buffer - behavior that is inappropriate for production code!

                func BufferReader

                func BufferReader(reader io.Reader) *Buffer

                  BufferReader returns a new gbytes.Buffer that wraps a reader. The reader's contents are read into the Buffer via io.Copy

                  func BufferWithBytes

                  func BufferWithBytes(bytes []byte) *Buffer

                    BufferWithBytes returns a new gbytes.Buffer seeded with the passed in bytes

                    func NewBuffer

                    func NewBuffer() *Buffer

                      NewBuffer returns a new gbytes.Buffer

                      func (*Buffer) CancelDetects

                      func (b *Buffer) CancelDetects()

                        CancelDetects cancels any pending detects and cleans up their goroutines. You should always call this when you're done with a set of Detect channels.

                        func (*Buffer) Close

                        func (b *Buffer) Close() error

                          Close signifies that the buffer will no longer be written to

                          func (*Buffer) Closed

                          func (b *Buffer) Closed() bool

                            Closed returns true if the buffer has been closed

                            func (*Buffer) Contents

                            func (b *Buffer) Contents() []byte

                              Contents returns all data ever written to the buffer.

                              func (*Buffer) Detect

                              func (b *Buffer) Detect(desired string, args ...interface{}) chan bool

                                Detect takes a regular expression and returns a channel.

                                The channel will receive true the first time data matching the regular expression is written to the buffer. The channel is subsequently closed and the buffer's read-cursor is fast-forwarded to just after the matching region.

                                You typically don't need to use Detect and should use the ghttp.Say matcher instead. Detect is useful, however, in cases where your code must be branch and handle different outputs written to the buffer.

                                For example, consider a buffer hooked up to the stdout of a client library. You may (or may not, depending on state outside of your control) need to authenticate the client library.

                                You could do something like:

                                select { case <-buffer.Detect("You are not logged in"):

                                //log in
                                

                                case <-buffer.Detect("Success"):

                                //carry on
                                

                                case <-time.After(time.Second):

                                //welp
                                

                                } buffer.CancelDetects()

                                You should always call CancelDetects after using Detect. This will close any channels that have not detected and clean up the goroutines that were spawned to support them.

                                Finally, you can pass detect a format string followed by variadic arguments. This will construct the regexp using fmt.Sprintf.

                                func (*Buffer) Read

                                func (b *Buffer) Read(d []byte) (int, error)

                                  Read implements the io.Reader interface. It advances the cursor as it reads.

                                  Returns an error if called after Close.

                                  func (*Buffer) Write

                                  func (b *Buffer) Write(p []byte) (n int, err error)

                                    Write implements the io.Writer interface

                                    type BufferProvider

                                    type BufferProvider interface {
                                    	Buffer() *Buffer
                                    }

                                      Objects satisfying the BufferProvider can be used with the Say matcher.