Struct assert_fs::fixture::NamedTempFile

pub struct NamedTempFile { /* fields omitted */ }

A potential file in the filesystem that is automatically deleted when it goes out of scope.

The NamedTempFile type creates a directory on the file system that is deleted once it goes out of scope. At construction, the NamedTempFile creates a new directory with a randomly generated name.

The constructor, [NamedTempFile::new(name)], creates directories in the location returned by std::env::temp_dir().

After creating a NamedTempFile, work with the file system by doing standard std::fs file system operations on its Path, which can be retrieved with NamedTempFile::path(). Once the NamedTempFile value is dropped, the parent directory will be deleted, along with the file. It is your responsibility to ensure that no further file system operations are attempted inside the temporary directory once it has been deleted.

Resource Leaking

Various platform-specific conditions may cause NamedTempFile to fail to delete the underlying directory. It’s important to ensure that handles (like File and ReadDir) to the file inside the directory is dropped before the NamedTempFile goes out of scope. The NamedTempFile destructor will silently ignore any errors in deleting the directory; to instead handle errors call NamedTempFile::close().

Note that if the program exits before the NamedTempFile destructor is run, such as via std::process::exit(), by segfaulting, or by receiving a signal like SIGINT, then the temporary directory will not be deleted.

Examples

Create a temporary file.

use assert_fs::fixture::NamedTempFile;

let tmp_file = NamedTempFile::new("foo.rs").unwrap();

// Ensure deletion happens.
tmp_file.close().unwrap();

Implementations

impl NamedTempFile

pub fn new<S>(name: S) -> Result<Self, FixtureError> where
    S: AsRef<OsStr>, 

Attempts to make a temporary file inside of env::temp_dir().

The file and parent directory will be automatically deleted once the returned NamedTempFile is destroyed.

Errors

If the parent directory can not be created, Err is returned.

Examples

use assert_fs::fixture::NamedTempFile;

let tmp_file = NamedTempFile::new("foo.rs").unwrap();

// Ensure deletion happens.
tmp_file.close().unwrap();

pub fn into_persistent_if(self, yes: bool) -> Self

Conditionally persist the temporary file for debug purposes.

Note: this operation is not reversible, i.e. into_persistent_if(false) is a no-op.

Examples

use assert_fs::fixture::NamedTempFile;

let tmp_file = NamedTempFile::new("foo.rs")
    .unwrap()
    .into_persistent_if(std::env::var_os("TEST_PERSIST_FILES").is_some());

// Ensure deletion happens.
tmp_file.close().unwrap();

pub fn into_persistent(self) -> Self

Persist the temporary file for debug purposes.

Note: this operation is not reversible, i.e. into_persistent_if(false) is a no-op.

Examples

use assert_fs::fixture::NamedTempFile;

let tmp_file = NamedTempFile::new("foo.rs")
    .unwrap()
    .into_persistent();

// Ensure deletion happens.
tmp_file.close().unwrap();

pub fn path(&self) -> &Path

Accesses the Path to the temporary file.

Examples

use assert_fs::fixture::NamedTempFile;

let tmp_file = NamedTempFile::new("foo.rs").unwrap();

println!("{}", tmp_file.path().display());

// Ensure deletion happens.
tmp_file.close().unwrap();

pub fn close(self) -> Result<(), FixtureError>

Closes and removes the temporary file and parent directory, returing a Result.

Although NamedTempFile removes the directory on drop, in the destructor any errors are ignored. To detect errors cleaning up the temporary directory, call close instead.

Errors

This function may return a variety of std::io::Errors that result from deleting the temporary file and parent directory, These errors may be platform specific.

Examples

use assert_fs::fixture::NamedTempFile;

let tmp_file = NamedTempFile::new("foo.rs").unwrap();

// Ensure deletion happens.
tmp_file.close().unwrap();

Methods from Deref<Target = Path>

pub fn as_os_str(&self) -> &OsStr

Yields the underlying OsStr slice.

Examples

use std::path::Path;

let os_str = Path::new("foo.txt").as_os_str();
assert_eq!(os_str, std::ffi::OsStr::new("foo.txt"));

pub fn to_str(&self) -> Option<&str>

Yields a &str slice if the Path is valid unicode.

This conversion may entail doing a check for UTF-8 validity. Note that validation is performed because non-UTF-8 strings are perfectly valid for some OS.

Examples

use std::path::Path;

let path = Path::new("foo.txt");
assert_eq!(path.to_str(), Some("foo.txt"));

pub fn to_string_lossy(&self) -> Cow<'_, str>

Converts a Path to a Cow<str>.

Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.

Examples

Calling to_string_lossy on a Path with valid unicode:

use std::path::Path;

let path = Path::new("foo.txt");
assert_eq!(path.to_string_lossy(), "foo.txt");

Had path contained invalid unicode, the to_string_lossy call might have returned "fo�.txt".

pub fn to_path_buf(&self) -> PathBuf

Converts a Path to an owned PathBuf.

Examples

use std::path::Path;

let path_buf = Path::new("foo.txt").to_path_buf();
assert_eq!(path_buf, std::path::PathBuf::from("foo.txt"));

pub fn is_absolute(&self) -> bool

Returns true if the Path is absolute, i.e., if it is independent of the current directory.

• On Unix, a path is absolute if it starts with the root, so is_absolute and has_root are equivalent.

• On Windows, a path is absolute if it has a prefix and starts with the root: c:\windows is absolute, while c:temp and \temp are not.

Examples

use std::path::Path;

assert!(!Path::new("foo.txt").is_absolute());

pub fn is_relative(&self) -> bool

Returns true if the Path is relative, i.e., not absolute.

See is_absolute’s documentation for more details.

Examples

use std::path::Path;

assert!(Path::new("foo.txt").is_relative());

pub fn has_root(&self) -> bool

Returns true if the Path has a root.

• On Unix, a path has a root if it begins with /.

• On Windows, a path has a root if it:

  • has no prefix and begins with a separator, e.g., \windows
  • has a prefix followed by a separator, e.g., c:\windows but not c:windows
  • has any non-disk prefix, e.g., \\server\share

Examples

use std::path::Path;

assert!(Path::new("/etc/passwd").has_root());

pub fn parent(&self) -> Option<&Path>

Returns the Path without its final component, if there is one.

Returns None if the path terminates in a root or prefix.

Examples

use std::path::Path;

let path = Path::new("/foo/bar");
let parent = path.parent().unwrap();
assert_eq!(parent, Path::new("/foo"));

let grand_parent = parent.parent().unwrap();
assert_eq!(grand_parent, Path::new("/"));
assert_eq!(grand_parent.parent(), None);

pub fn ancestors(&self) -> Ancestors<'_>

Produces an iterator over Path and its ancestors.

The iterator will yield the Path that is returned if the parent method is used zero or more times. That means, the iterator will yield &self, &self.parent().unwrap(), &self.parent().unwrap().parent().unwrap() and so on. If the parent method returns None, the iterator will do likewise. The iterator will always yield at least one value, namely &self.

Examples

use std::path::Path;

let mut ancestors = Path::new("/foo/bar").ancestors();
assert_eq!(ancestors.next(), Some(Path::new("/foo/bar")));
assert_eq!(ancestors.next(), Some(Path::new("/foo")));
assert_eq!(ancestors.next(), Some(Path::new("/")));
assert_eq!(ancestors.next(), None);

let mut ancestors = Path::new("../foo/bar").ancestors();
assert_eq!(ancestors.next(), Some(Path::new("../foo/bar")));
assert_eq!(ancestors.next(), Some(Path::new("../foo")));
assert_eq!(ancestors.next(), Some(Path::new("..")));
assert_eq!(ancestors.next(), Some(Path::new("")));
assert_eq!(ancestors.next(), None);

pub fn file_name(&self) -> Option<&OsStr>

Returns the final component of the Path, if there is one.

If the path is a normal file, this is the file name. If it’s the path of a directory, this is the directory name.

Returns None if the path terminates in ...

Examples

use std::path::Path;
use std::ffi::OsStr;

assert_eq!(Some(OsStr::new("bin")), Path::new("/usr/bin/").file_name());
assert_eq!(Some(OsStr::new("foo.txt")), Path::new("tmp/foo.txt").file_name());
assert_eq!(Some(OsStr::new("foo.txt")), Path::new("foo.txt/.").file_name());
assert_eq!(Some(OsStr::new("foo.txt")), Path::new("foo.txt/.//").file_name());
assert_eq!(None, Path::new("foo.txt/..").file_name());
assert_eq!(None, Path::new("/").file_name());

pub fn strip_prefix<P>(&self, base: P) -> Result<&Path, StripPrefixError> where
    P: AsRef<Path>, 

Returns a path that, when joined onto base, yields self.

Errors

If base is not a prefix of self (i.e., starts_with returns false), returns Err.

Examples

use std::path::{Path, PathBuf};

let path = Path::new("/test/haha/foo.txt");

assert_eq!(path.strip_prefix("/"), Ok(Path::new("test/haha/foo.txt")));
assert_eq!(path.strip_prefix("/test"), Ok(Path::new("haha/foo.txt")));
assert_eq!(path.strip_prefix("/test/"), Ok(Path::new("haha/foo.txt")));
assert_eq!(path.strip_prefix("/test/haha/foo.txt"), Ok(Path::new("")));
assert_eq!(path.strip_prefix("/test/haha/foo.txt/"), Ok(Path::new("")));

assert!(path.strip_prefix("test").is_err());
assert!(path.strip_prefix("/haha").is_err());

let prefix = PathBuf::from("/test/");
assert_eq!(path.strip_prefix(prefix), Ok(Path::new("haha/foo.txt")));

pub fn starts_with<P>(&self, base: P) -> bool where
    P: AsRef<Path>, 

Determines whether base is a prefix of self.

Only considers whole path components to match.

Examples

use std::path::Path;

let path = Path::new("/etc/passwd");

assert!(path.starts_with("/etc"));
assert!(path.starts_with("/etc/"));
assert!(path.starts_with("/etc/passwd"));
assert!(path.starts_with("/etc/passwd/")); // extra slash is okay
assert!(path.starts_with("/etc/passwd///")); // multiple extra slashes are okay

assert!(!path.starts_with("/e"));
assert!(!path.starts_with("/etc/passwd.txt"));

assert!(!Path::new("/etc/foo.rs").starts_with("/etc/foo"));

pub fn ends_with<P>(&self, child: P) -> bool where
    P: AsRef<Path>, 

Determines whether child is a suffix of self.

Only considers whole path components to match.

Examples

use std::path::Path;

let path = Path::new("/etc/resolv.conf");

assert!(path.ends_with("resolv.conf"));
assert!(path.ends_with("etc/resolv.conf"));
assert!(path.ends_with("/etc/resolv.conf"));

assert!(!path.ends_with("/resolv.conf"));
assert!(!path.ends_with("conf")); // use .extension() instead

pub fn file_stem(&self) -> Option<&OsStr>

Extracts the stem (non-extension) portion of self.file_name.

The stem is:

• None, if there is no file name;
• The entire file name if there is no embedded .;
• The entire file name if the file name begins with . and has no other .s within;
• Otherwise, the portion of the file name before the final .

Examples

use std::path::Path;

assert_eq!("foo", Path::new("foo.rs").file_stem().unwrap());
assert_eq!("foo.tar", Path::new("foo.tar.gz").file_stem().unwrap());

pub fn extension(&self) -> Option<&OsStr>

Extracts the extension of self.file_name, if possible.

The extension is:

• None, if there is no file name;
• None, if there is no embedded .;
• None, if the file name begins with . and has no other .s within;
• Otherwise, the portion of the file name after the final .

Examples

use std::path::Path;

assert_eq!("rs", Path::new("foo.rs").extension().unwrap());
assert_eq!("gz", Path::new("foo.tar.gz").extension().unwrap());

#[must_use]

pub fn join<P>(&self, path: P) -> PathBuf where
    P: AsRef<Path>, 

Creates an owned PathBuf with path adjoined to self.

See PathBuf::push for more details on what it means to adjoin a path.

Examples

use std::path::{Path, PathBuf};

assert_eq!(Path::new("/etc").join("passwd"), PathBuf::from("/etc/passwd"));

pub fn with_file_name<S>(&self, file_name: S) -> PathBuf where
    S: AsRef<OsStr>, 

Creates an owned PathBuf like self but with the given file name.

See PathBuf::set_file_name for more details.

Examples

use std::path::{Path, PathBuf};

let path = Path::new("/tmp/foo.txt");
assert_eq!(path.with_file_name("bar.txt"), PathBuf::from("/tmp/bar.txt"));

let path = Path::new("/tmp");
assert_eq!(path.with_file_name("var"), PathBuf::from("/var"));

pub fn with_extension<S>(&self, extension: S) -> PathBuf where
    S: AsRef<OsStr>, 

Creates an owned PathBuf like self but with the given extension.

See PathBuf::set_extension for more details.

Examples

use std::path::{Path, PathBuf};

let path = Path::new("foo.rs");
assert_eq!(path.with_extension("txt"), PathBuf::from("foo.txt"));

let path = Path::new("foo.tar.gz");
assert_eq!(path.with_extension(""), PathBuf::from("foo.tar"));
assert_eq!(path.with_extension("xz"), PathBuf::from("foo.tar.xz"));
assert_eq!(path.with_extension("").with_extension("txt"), PathBuf::from("foo.txt"));

pub fn components(&self) -> Components<'_>

Produces an iterator over the Components of the path.

When parsing the path, there is a small amount of normalization:

• Repeated separators are ignored, so a/b and a//b both have a and b as components.

• Occurrences of . are normalized away, except if they are at the beginning of the path. For example, a/./b, a/b/, a/b/. and a/b all have a and b as components, but ./a/b starts with an additional CurDir component.

• A trailing slash is normalized away, /a/b and /a/b/ are equivalent.

Note that no other normalization takes place; in particular, a/c and a/b/../c are distinct, to account for the possibility that b is a symbolic link (so its parent isn’t a).

Examples

use std::path::{Path, Component};
use std::ffi::OsStr;

let mut components = Path::new("/tmp/foo.txt").components();

assert_eq!(components.next(), Some(Component::RootDir));
assert_eq!(components.next(), Some(Component::Normal(OsStr::new("tmp"))));
assert_eq!(components.next(), Some(Component::Normal(OsStr::new("foo.txt"))));
assert_eq!(components.next(), None)

pub fn iter(&self) -> Iter<'_>

Produces an iterator over the path’s components viewed as OsStr slices.

For more information about the particulars of how the path is separated into components, see components.

Examples

use std::path::{self, Path};
use std::ffi::OsStr;

let mut it = Path::new("/tmp/foo.txt").iter();
assert_eq!(it.next(), Some(OsStr::new(&path::MAIN_SEPARATOR.to_string())));
assert_eq!(it.next(), Some(OsStr::new("tmp")));
assert_eq!(it.next(), Some(OsStr::new("foo.txt")));
assert_eq!(it.next(), None)

pub fn display(&self) -> Display<'_>

Returns an object that implements Display for safely printing paths that may contain non-Unicode data. This may perform lossy conversion, depending on the platform. If you would like an implementation which escapes the path please use Debug instead.

Examples

use std::path::Path;

let path = Path::new("/tmp/foo.rs");

println!("{}", path.display());

pub fn metadata(&self) -> Result<Metadata, Error>

Queries the file system to get information about a file, directory, etc.

This function will traverse symbolic links to query information about the destination file.

This is an alias to fs::metadata.

Examples

use std::path::Path;

let path = Path::new("/Minas/tirith");
let metadata = path.metadata().expect("metadata call failed");
println!("{:?}", metadata.file_type());

pub fn symlink_metadata(&self) -> Result<Metadata, Error>

Queries the metadata about a file without following symlinks.

This is an alias to fs::symlink_metadata.

Examples

use std::path::Path;

let path = Path::new("/Minas/tirith");
let metadata = path.symlink_metadata().expect("symlink_metadata call failed");
println!("{:?}", metadata.file_type());

pub fn canonicalize(&self) -> Result<PathBuf, Error>

Returns the canonical, absolute form of the path with all intermediate components normalized and symbolic links resolved.

This is an alias to fs::canonicalize.

Examples

use std::path::{Path, PathBuf};

let path = Path::new("/foo/test/../test/bar.rs");
assert_eq!(path.canonicalize().unwrap(), PathBuf::from("/foo/test/bar.rs"));

pub fn read_link(&self) -> Result<PathBuf, Error>

Reads a symbolic link, returning the file that the link points to.

This is an alias to fs::read_link.

Examples

use std::path::Path;

let path = Path::new("/laputa/sky_castle.rs");
let path_link = path.read_link().expect("read_link call failed");

pub fn read_dir(&self) -> Result<ReadDir, Error>

Returns an iterator over the entries within a directory.

The iterator will yield instances of io::Result<fs::DirEntry>. New errors may be encountered after an iterator is initially constructed.

This is an alias to fs::read_dir.

Examples

use std::path::Path;

let path = Path::new("/laputa");
for entry in path.read_dir().expect("read_dir call failed") {
    if let Ok(entry) = entry {
        println!("{:?}", entry.path());
    }
}

pub fn exists(&self) -> bool

Returns true if the path points at an existing entity.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return false.

If you cannot access the directory containing the file, e.g., because of a permission error, this will return false.

Examples

use std::path::Path;
assert!(!Path::new("does_not_exist.txt").exists());

See Also

This is a convenience function that coerces errors to false. If you want to check errors, call fs::metadata.

pub fn try_exists(&self) -> Result<bool, Error>

🔬 This is a nightly-only experimental API. (path_try_exists)

Returns Ok(true) if the path points at an existing entity.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return Ok(false).

As opposed to the exists() method, this one doesn’t silently ignore errors unrelated to the path not existing. (E.g. it will return Err(_) in case of permission denied on some of the parent directories.)

Examples

#![feature(path_try_exists)]

use std::path::Path;
assert!(!Path::new("does_not_exist.txt").try_exists().expect("Can't check existence of file does_not_exist.txt"));
assert!(Path::new("/root/secret_file.txt").try_exists().is_err());

pub fn is_file(&self) -> bool

Returns true if the path exists on disk and is pointing at a regular file.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return false.

If you cannot access the directory containing the file, e.g., because of a permission error, this will return false.

Examples

use std::path::Path;
assert_eq!(Path::new("./is_a_directory/").is_file(), false);
assert_eq!(Path::new("a_file.txt").is_file(), true);

See Also

This is a convenience function that coerces errors to false. If you want to check errors, call fs::metadata and handle its Result. Then call fs::Metadata::is_file if it was Ok.

When the goal is simply to read from (or write to) the source, the most reliable way to test the source can be read (or written to) is to open it. Only using is_file can break workflows like diff <( prog_a ) on a Unix-like system for example. See fs::File::open or fs::OpenOptions::open for more information.

pub fn is_dir(&self) -> bool

Returns true if the path exists on disk and is pointing at a directory.

This function will traverse symbolic links to query information about the destination file. In case of broken symbolic links this will return false.

If you cannot access the directory containing the file, e.g., because of a permission error, this will return false.

Examples

use std::path::Path;
assert_eq!(Path::new("./is_a_directory/").is_dir(), true);
assert_eq!(Path::new("a_file.txt").is_dir(), false);

See Also

This is a convenience function that coerces errors to false. If you want to check errors, call fs::metadata and handle its Result. Then call fs::Metadata::is_dir if it was Ok.

Trait Implementations

impl AsRef<Path> for NamedTempFile

fn as_ref(&self) -> &Path

Performs the conversion.

impl Deref for NamedTempFile

type Target = Path

The resulting type after dereferencing.

fn deref(&self) -> &Path

Dereferences the value.

impl FileTouch for NamedTempFile

fn touch(&self) -> Result<(), FixtureError>

Create an empty file at ChildPath.

impl FileWriteBin for NamedTempFile

fn write_binary(&self, data: &[u8]) -> Result<(), FixtureError>

Write a binary file at ChildPath.

impl FileWriteFile for NamedTempFile

fn write_file(&self, data: &Path) -> Result<(), FixtureError>

Write (copy) a file to ChildPath.

impl FileWriteStr for NamedTempFile

fn write_str(&self, data: &str) -> Result<(), FixtureError>

Write a text file at ChildPath.

impl PathAssert for NamedTempFile

fn assert<I, P>(&self, pred: I) -> &Self where
    I: IntoPathPredicate<P>,
    P: Predicate<Path>, 

Assert the state of files within TempDir.