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

    This section is empty.

    Functions

    func Say

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

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

      Ω(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 asser 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.

      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 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.