Regression tests (#422)

* Created regression tests for the table of contents

* Refactoring to make the test more readable

* Fixed some bitrot and removed the (now redundant) tests/helper module

* Removed the include_str!() stuff and use just the dummy book for testing

* Regression tests now pass again!

* Pinned a `*` dependency to use a particular version

* Made sure test mocks return errors instead of panicking

* Addressed the rest of @budziq's review

* Replaced a file open/read with file_to_string

Cargo.toml

@@ -43,6 +43,11 @@ ws = { version = "0.7", optional = true}
 [build-dependencies]
 error-chain = "0.11"
 
+[dev-dependencies]
+select = "0.4"
+pretty_assertions = "0.4"
+walkdir = "1.0"
+
 [features]
 default = ["output", "watch", "serve"]
 debug = []

tests/dummy_book/mod.rs

@@ -0,0 +1,116 @@
+//! This will create an entire book in a temporary directory using some
+//! dummy contents from the `tests/dummy-book/` directory.
+
+// Not all features are used in all test crates, so...
+#![allow(dead_code, unused_variables, unused_imports, unused_extern_crates)]
+extern crate mdbook;
+extern crate tempdir;
+extern crate walkdir;
+
+use std::path::Path;
+use std::fs::{self, File};
+use std::io::{Read, Write};
+use mdbook::errors::*;
+use mdbook::utils::fs::file_to_string;
+
+// The funny `self::` here is because we've got an `extern crate ...` and are
+// in a submodule
+use self::tempdir::TempDir;
+use self::mdbook::MDBook;
+use self::walkdir::WalkDir;
+
+
+/// Create a dummy book in a temporary directory, using the contents of
+/// `SUMMARY_MD` as a guide.
+///
+/// The "Nested Chapter" file contains a code block with a single
+/// `assert!($TEST_STATUS)`. If you want to check MDBook's testing
+/// functionality, `$TEST_STATUS` can be substitute for either `true` or
+/// `false`. This is done using the `passing_test` parameter.
+#[derive(Clone, Debug, PartialEq)]
+pub struct DummyBook {
+    passing_test: bool,
+}
+
+impl DummyBook {
+    /// Create a new `DummyBook` with all the defaults.
+    pub fn new() -> DummyBook {
+        DummyBook { passing_test: true }
+    }
+
+    /// Whether the doc-test included in the "Nested Chapter" should pass or
+    /// fail (it passes by default).
+    pub fn with_passing_test(&mut self, test_passes: bool) -> &mut DummyBook {
+        self.passing_test = test_passes;
+        self
+    }
+
+    /// Write a book to a temporary directory using the provided settings.
+    pub fn build(&self) -> Result<TempDir> {
+        let temp = TempDir::new("dummy_book").chain_err(|| "Unable to create temp directory")?;
+
+        let dummy_book_root = Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/dummy_book");
+        recursive_copy(&dummy_book_root, temp.path()).chain_err(|| {
+                                                                     "Couldn't copy files into a \
+                                                                      temporary directory"
+                                                                 })?;
+
+        let sub_pattern = if self.passing_test { "true" } else { "false" };
+        let file_containing_test = temp.path().join("src/first/nested.md");
+        replace_pattern_in_file(&file_containing_test, "$TEST_STATUS", sub_pattern)?;
+
+        Ok(temp)
+    }
+}
+
+fn replace_pattern_in_file(filename: &Path, from: &str, to: &str) -> Result<()> {
+    let contents = file_to_string(filename)?;
+    File::create(filename)?.write_all(contents.replace(from, to).as_bytes())?;
+
+    Ok(())
+}
+
+/// Read the contents of the provided file into memory and then iterate through
+/// the list of strings asserting that the file contains all of them.
+pub fn assert_contains_strings<P: AsRef<Path>>(filename: P, strings: &[&str]) {
+    let filename = filename.as_ref();
+    let content = file_to_string(filename).expect("Couldn't read the file's contents");
+
+    for s in strings {
+        assert!(content.contains(s),
+                "Searching for {:?} in {}\n\n{}",
+                s,
+                filename.display(),
+                content);
+    }
+}
+
+
+
+/// Recursively copy an entire directory tree to somewhere else (a la `cp -r`).
+fn recursive_copy<A: AsRef<Path>, B: AsRef<Path>>(from: A, to: B) -> Result<()> {
+    let from = from.as_ref();
+    let to = to.as_ref();
+
+    for entry in WalkDir::new(&from) {
+        let entry = entry.chain_err(|| "Unable to inspect directory entry")?;
+
+        let original_location = entry.path();
+        let relative = original_location.strip_prefix(&from)
+                                        .expect("`original_location` is inside the `from` \
+                                                 directory");
+        let new_location = to.join(relative);
+
+        if original_location.is_file() {
+            if let Some(parent) = new_location.parent() {
+                fs::create_dir_all(parent).chain_err(|| "Couldn't create directory")?;
+            }
+
+            fs::copy(&original_location, &new_location).chain_err(|| {
+                                                                      "Unable to copy file contents"
+                                                                  })?;
+        }
+    }
+
+    Ok(())
+}

tests/dummy/book/SUMMARY.md → tests/dummy_book/src/SUMMARY.md

@@ -4,6 +4,7 @@
 
 - [First Chapter](./first/index.md)
     - [Nested Chapter](./first/nested.md)
+---
 - [Second Chapter](./second.md)
 
 [Conclusion](./conclusion.md)