Add File doesNotExist assertion

assertk/src/jvmMain/kotlin/assertk/assertions/file.kt

@@ -46,6 +46,14 @@ fun Assert<File>.exists() = given { actual ->
  expected("to exist")
 }
 
+/**
+ * Asserts the file does not exists.
+ */
+fun Assert<File>.doesNotExist() = given { actual ->
+ if (!actual.exists()) return
+ expected("not to exist")
+}
+
 /**
  * Asserts the file is a directory.
  * @see [isFile]

assertk/src/jvmTest/kotlin/test/assertk/assertions/FileTest.kt

@@ -10,6 +10,9 @@ class FileTest {
 
  val file = File.createTempFile("exists", "txt")
  val directory = Files.createTempDirectory("isDirectory").toFile()
+ val missing = File("/this/is/not/a/real/file/and/should/not/exist.txt").also {
+ assertFalse(it.exists())
+ }
 
  //region exists
  @Test
@@ -19,15 +22,28 @@ class FileTest {
 
  @Test
  fun exists_with_nonexistent_file_fails() {
- val tempFile = File.createTempFile("exists", "txt")
- tempFile.delete()
  val error = assertFailsWith<AssertionError> {
- assertThat(tempFile).exists()
+ assertThat(missing).exists()
  }
  assertEquals("expected to exist", error.message)
  }
  //endregion
 
+ //region does not exist
+ @Test
+ fun doesNotExist_with_missing_file_passes() {
+ assertThat(missing).doesNotExist()
+ }
+
+ @Test
+ fun doesNotExist_with_nonexistent_file_fails() {
+ val error = assertFailsWith<AssertionError> {
+ assertThat(file).doesNotExist()
+ }
+ assertEquals("expected not to exist", error.message)
+ }
+ //endregion
+
  //region isDirectory
  @Test
  fun isDirectory_value_directory_passes() {