Struct requestty_ui::backend::TestBackend [−][src]
pub struct TestBackend { /* fields omitted */ }Expand description
A backend that can be used for tests.
When asserting equality, it is recommended to use TestBackend::assert_eq or
assert_backend_snapshot instead of assert_eq.
Implementations
Creates a new TestBackend with the cursor starting at the offsets given by the layout.
Creates a new TestBackend from the lines. There must be <= size.height lines, and
<= size.width chars per line.
It is not necessary to fill the lines so that it matches the dimensions of size exactly. Padding will be added to the end as required.
Panics
It panics if there are more than size.height lines or more than size.width chars per
line.
Clears all the cells and moves the cursor to the offsets given by the layout.
Writes all the cells of the TestBackend to the given backend.
A screenshot of what the printed output looks like:

This is supported on crate features crossterm or termion only.
crossterm or termion only.Writes all the cells of the TestBackend with the default backend (see get_backend).
A screenshot of what the printed output looks like:

Trait Implementations
Enables raw mode.
Disables raw mode.
Hides the cursor.
Shows the cursor.
Gets the cursor position as (col, row). The top-left cell is (0, 0).
Moves the cursor to given position. The top-left cell is (0, 0).
Moves the cursor relative to the current position as per the direction.
Scrolls the terminal the given number of rows. Read more
Sets the given attributes removing ones which were previous applied.
Writes all the cells of the TestBackend using write_to_buf.
A screenshot of what the printed output looks like:

Visual equality to another backend. This means that if the cells of both backends were rendered on a terminal, they would look the same. It however does not mean, that the hidden scrollback buffer is the same, or the current attributes are the same, or event the cursor position if it is hidden.
Write a buffer into this writer, returning how many bytes were written. Read more
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
can_vector)Determines if this Writer has an efficient write_vectored
implementation. Read more
Attempts to write an entire buffer into this writer. Read more
write_all_vectored)Attempts to write multiple buffers into this writer. Read more
Writes a formatted string into this writer, returning any error encountered. Read more
Auto Trait Implementations
impl RefUnwindSafe for TestBackend
impl Send for TestBackend
impl Sync for TestBackend
impl Unpin for TestBackend
impl UnwindSafe for TestBackend
Blanket Implementations
Mutably borrows from an owned value. Read more
Executes the given command directly.
The given command its ANSI escape code will be written and flushed onto Self.
Arguments
-
The command that you want to execute directly.
Example
use std::io::{Write, stdout};
use crossterm::{Result, ExecutableCommand, style::Print};
fn main() -> Result<()> {
// will be executed directly
stdout()
.execute(Print("sum:\n".to_string()))?
.execute(Print(format!("1 + 1= {} ", 1 + 1)))?;
Ok(())
// ==== Output ====
// sum:
// 1 + 1 = 2
}Have a look over at the Command API for more details.
Notes
- In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
- In case of Windows versions lower than 10, a direct WinAPI call will be made.
The reason for this is that Windows versions lower than 10 do not support ANSI codes,
and can therefore not be written to the given
writer. Therefore, there is no difference between execute and queue for those old Windows versions.
Switch to raw mode. Read more
Queues the given command for further execution.
Queued commands will be executed in the following cases:
- When
flushis called manually on the given type implementingio::Write. - The terminal will
flushautomatically if the buffer is full. - Each line is flushed in case of
stdout, because it is line buffered.
Arguments
-
The command that you want to queue for later execution.
Examples
use std::io::{Write, stdout};
use crossterm::{Result, QueueableCommand, style::Print};
fn main() -> Result<()> {
let mut stdout = stdout();
// `Print` will executed executed when `flush` is called.
stdout
.queue(Print("foo 1\n".to_string()))?
.queue(Print("foo 2".to_string()))?;
// some other code (no execution happening here) ...
// when calling `flush` on `stdout`, all commands will be written to the stdout and therefore executed.
stdout.flush()?;
Ok(())
// ==== Output ====
// foo 1
// foo 2
}Have a look over at the Command API for more details.
Notes
- In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
- In case of Windows versions lower than 10, a direct WinAPI call will be made.
The reason for this is that Windows versions lower than 10 do not support ANSI codes,
and can therefore not be written to the given
writer. Therefore, there is no difference between execute and queue for those old Windows versions.