2 files changed, 72 insertions, 0 deletions

diff --git a/tests/testutils/Cargo.toml b/tests/testutils/Cargo.toml
new file mode 100644
index 000000000..9003822ee
--- /dev/null
+++ b/tests/testutils/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "testutils"
+version = "0.1.0"
+authors = ["Aleksey Kladov <[email protected]>"]
+
+[dependencies]
+file = "1.0"
+difference = "1.0.0"
diff --git a/tests/testutils/src/lib.rs b/tests/testutils/src/lib.rs
new file mode 100644
index 000000000..9fc85cc24
--- /dev/null
+++ b/tests/testutils/src/lib.rs
@@ -0,0 +1,64 @@
+extern crate difference;
+extern crate file;
+
+use std::path::{PathBuf, Path};
+use std::fs::read_dir;
+
+use difference::Changeset;
+
+pub fn assert_equal_text(
+    expected: &str,
+    actual: &str,
+    path: &Path
+) {
+    if expected != actual {
+        print_difference(expected, actual, path)
+    }
+}
+
+pub fn collect_tests(paths: &[&str]) -> Vec<PathBuf> {
+    paths.iter().flat_map(|path|  {
+        let path = test_data_dir().join(path);
+        test_from_dir(&path).into_iter()
+    }).collect()
+}
+
+fn test_from_dir(dir: &Path) -> Vec<PathBuf> {
+    let mut acc = Vec::new();
+    for file in read_dir(&dir).unwrap() {
+        let file = file.unwrap();
+        let path = file.path();
+        if path.extension().unwrap_or_default() == "rs" {
+            acc.push(path);
+        }
+    }
+    acc.sort();
+    acc
+}
+
+fn print_difference(expected: &str, actual: &str, path: &Path) {
+    let dir = project_dir();
+    let path = path.strip_prefix(&dir).unwrap_or_else(|_| path);
+    println!("\nfile: {}", path.display());
+    if expected.trim() == actual.trim() {
+        println!("whitespace difference");
+        println!("rewriting the file");
+        file::put_text(path, actual).unwrap();
+    } else {
+        let changeset = Changeset::new(actual, expected, "\n");
+        println!("{}", changeset);
+    }
+    panic!("Comparison failed")
+}
+
+fn project_dir() -> PathBuf {
+    let dir = env!("CARGO_MANIFEST_DIR");
+    PathBuf::from(dir)
+        .parent().unwrap()
+        .parent().unwrap()
+        .to_owned()
+}
+
+fn test_data_dir() -> PathBuf {
+    project_dir().join("tests/data")
+}
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