Unit test collection module

.gitignore

@@ -1 +1,2 @@
 /target
+/codecov

README.md

@@ -12,21 +12,23 @@ cargo install grcov
 ### Generating Code Coverage
 
 ```sh
-cargo clean
+env CARGO_TARGET_DIR=codecov \
+    cargo clean
 env RUSTFLAGS="-C instrument-coverage" \
-    LLVM_PROFILE_FILE="target/debug/profraw/musichoard-%p-%m.profraw" \
+    LLVM_PROFILE_FILE="codecov/debug/profraw/musichoard-%p-%m.profraw" \
+    CARGO_TARGET_DIR=codecov \
     cargo test
-grcov target/debug/profraw \
-      --binary-path ./target/debug/ \
+grcov codecov/debug/profraw \
+      --binary-path ./codecov/debug/ \
       --output-types html \
       --source-dir . \
       --ignore-not-existing \
       --ignore "tests/*" \
       --ignore "src/main.rs" \
       --excl-start "mod tests \{" \
-      --output-path ./target/debug/coverage/
-xdg-open target/debug/coverage/index.html
+      --output-path ./codecov/debug/coverage/
+xdg-open codecov/debug/coverage/index.html
 ```
 
-Note that some changes may not be visible until `target/debug/coverage` is removed and the `grcov`
+Note that some changes may not be visible until `codecov/debug/coverage` is removed and the `grcov`
 command is rerun.

src/collection/mod.rs

@@ -12,7 +12,7 @@ use crate::{
 pub type Collection = Vec<Artist>;
 
 /// Error type for collection manager.
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum Error {
     /// The [`CollectionManager`] failed to read/write from/to the library.
     LibraryError(String),
@@ -81,3 +81,91 @@ impl CollectionManager {
         &self.collection
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use mockall::predicate;
+
+    use crate::{
+        database::{self, MockDatabase},
+        library::{self, MockLibrary, Query},
+        tests::COLLECTION,
+    };
+
+    use super::{CollectionManager, Error};
+
+    #[test]
+    fn read_get_write() {
+        let mut library = MockLibrary::new();
+        let mut database = MockDatabase::new();
+
+        let library_input = Query::default();
+        let library_result = Ok(COLLECTION.to_owned());
+
+        let database_input = COLLECTION.to_owned();
+        let database_result = Ok(());
+
+        library
+            .expect_list()
+            .with(predicate::eq(library_input))
+            .times(1)
+            .return_once(|_| library_result);
+
+        database
+            .expect_write()
+            .with(predicate::eq(database_input))
+            .times(1)
+            .return_once(|_| database_result);
+
+        let mut collection_manager = CollectionManager::new(Box::new(library), Box::new(database));
+
+        collection_manager.rescan_library().unwrap();
+        assert_eq!(collection_manager.get_collection(), &*COLLECTION);
+        collection_manager.save_to_database().unwrap();
+    }
+
+    #[test]
+    fn library_error() {
+        let mut library = MockLibrary::new();
+        let database = MockDatabase::new();
+
+        let library_result = Err(library::Error::InvalidData(String::from("invalid data")));
+
+        library
+            .expect_list()
+            .times(1)
+            .return_once(|_| library_result);
+
+        let mut collection_manager = CollectionManager::new(Box::new(library), Box::new(database));
+
+        let actual_err = collection_manager.rescan_library().unwrap_err();
+        let expected_err = Error::LibraryError(
+            library::Error::InvalidData(String::from("invalid data")).to_string(),
+        );
+
+        assert_eq!(actual_err, expected_err);
+        assert_eq!(actual_err.to_string(), expected_err.to_string());
+    }
+
+    #[test]
+    fn database_error() {
+        let library = MockLibrary::new();
+        let mut database = MockDatabase::new();
+
+        let database_result = Err(database::Error::IoError(String::from("I/O error")));
+
+        database
+            .expect_write()
+            .times(1)
+            .return_once(|_| database_result);
+
+        let mut collection_manager = CollectionManager::new(Box::new(library), Box::new(database));
+
+        let actual_err = collection_manager.save_to_database().unwrap_err();
+        let expected_err =
+            Error::DatabaseError(database::Error::IoError(String::from("I/O error")).to_string());
+
+        assert_eq!(actual_err, expected_err);
+        assert_eq!(actual_err.to_string(), expected_err.to_string());
+    }
+}

src/database/json.rs

@@ -8,7 +8,7 @@ use crate::collection::Collection;
 #[cfg(test)]
 use mockall::automock;
 
-use super::{Database, DatabaseRead, DatabaseWrite, Error};
+use super::{Database, Error};
 
 impl From<serde_json::Error> for Error {
     fn from(err: serde_json::Error) -> Error {
@@ -38,15 +38,13 @@ impl JsonDatabase {
     }
 }
 
-impl DatabaseRead for JsonDatabase {
+impl Database for JsonDatabase {
     fn read(&self, collection: &mut Collection) -> Result<(), Error> {
         let serialized = self.backend.read()?;
         *collection = serde_json::from_str(&serialized)?;
         Ok(())
     }
-}
 
-impl DatabaseWrite for JsonDatabase {
     fn write(&mut self, collection: &Collection) -> Result<(), Error> {
         let serialized = serde_json::to_string(&collection)?;
         self.backend.write(&serialized)?;
@@ -54,8 +52,6 @@ impl DatabaseWrite for JsonDatabase {
     }
 }
 
-impl Database for JsonDatabase {}
-
 /// JSON database backend that uses a local file for persistent storage.
 pub struct JsonDatabaseFileBackend {
     path: PathBuf,

src/database/mod.rs

@@ -2,6 +2,9 @@
 
 use std::fmt;
 
+#[cfg(test)]
+use mockall::automock;
+
 use crate::collection::Collection;
 
 pub mod json;
@@ -32,17 +35,12 @@ impl From<std::io::Error> for Error {
     }
 }
 
-/// Trait for database reads.
-pub trait DatabaseRead {
+/// Trait for interacting with the database.
+#[cfg_attr(test, automock)]
+pub trait Database {
     /// Read collection from the database.
     fn read(&self, collection: &mut Collection) -> Result<(), Error>;
-}
 
-/// Trait for database writes.
-pub trait DatabaseWrite {
     /// Write collection to the database.
     fn write(&mut self, collection: &Collection) -> Result<(), Error>;
 }
-
-/// Trait for database reads and writes.
-pub trait Database: DatabaseRead + DatabaseWrite {}

src/library/mod.rs

@@ -2,11 +2,15 @@
 
 use std::{num::ParseIntError, str::Utf8Error, fmt};
 
+#[cfg(test)]
+use mockall::automock;
+
 use crate::Artist;
 
 pub mod beets;
 
 /// A single query option.
+#[derive(Debug, PartialEq, Eq)]
 pub enum QueryOption<T> {
     /// Inclusive query.
     Include(T),
@@ -36,7 +40,7 @@ impl<T> Default for QueryOption<T> {
 }
 
 /// Options for refining library queries.
-#[derive(Default)]
+#[derive(Debug, Default, PartialEq, Eq)]
 pub struct Query {
     album_artist: QueryOption<String>,
     album_year: QueryOption<u32>,
@@ -142,6 +146,7 @@ impl From<Utf8Error> for Error {
 }
 
 /// Trait for interacting with the music library.
+#[cfg_attr(test, automock)]
 pub trait Library {
     /// List lirbary items that match the a specific query.
     fn list(&mut self, query: &Query) -> Result<Vec<Artist>, Error>;

tests/database/json.rs

@@ -3,7 +3,7 @@ use std::{fs, path::PathBuf};
 use musichoard::{
     database::{
         json::{JsonDatabase, JsonDatabaseFileBackend},
-        DatabaseRead, DatabaseWrite,
+        Database,
     },
     Artist,
 };