Add run_solver() function for testing

src/solvers.rs

@@ -23,6 +23,10 @@ pub trait Solver {
     fn process_data<R: BufRead>(&self, reader: R) -> (u64, u64);
 }
 
+// The "../../data" and "../../../data" paths are useful for running the binary from
+// "target/release/" directory with "data/" directory in package root or parent directory.
+const DATA_PATHS: &'static [&'static str] = &["./data", "../data", "../../data", "../../../data"];
+
 pub fn run<S: Solver>(solver: S) {
     println!(
         "--- Day {}: {} ---",
@@ -30,29 +34,29 @@ pub fn run<S: Solver>(solver: S) {
         solver.puzzle_name()
     );
 
-    // TODO: Convert to constant and add "example" paths.
+    match run_solver(solver, &DATA_PATHS) {
-    // The "../../data" and "../../../data" paths are useful for running the binary from
+        Ok(result) => print_result(result),
-    // "target/release/" directory with "data/" directory in package root or parent directory.
+        Err(error) => eprintln!("{}", error),
-    let paths = vec!["./data", "../data", "../../data", "../../../data"];
+    }
+}
 
-    let filename = sanitise_file_name::sanitise(solver.puzzle_name())
+pub fn run_solver<S: Solver>(solver: S, paths: &[&str]) -> Result<(u64, u64), String> {
+    let reader = read_data_file(input_filename(solver.puzzle_name()), paths)?;
+    Ok(solver.process_data(reader))
+}
+
+fn input_filename(puzzle_name: &str) -> String {
+    sanitise_file_name::sanitise(puzzle_name)
         .to_lowercase()
         .replace(" ", "_")
-        + ".txt";
+        + ".txt"
-    match read_data_file(filename, &paths) {
-        Ok(reader) => {
-            let result = solver.process_data(reader);
-            print_result(result);
-        }
-        Err(error) => eprintln!("{}", error),
-    };
 }
 
 fn print_result(result: (u64, u64)) {
     println!("Part 1: {:?}\nPart 2: {:?}\n", result.0, result.1);
 }
 
-fn read_data_file<T>(filename: String, search_paths: &Vec<T>) -> Result<io::BufReader<File>, String>
+fn read_data_file<T>(filename: String, search_paths: &[T]) -> Result<io::BufReader<File>, String>
 where
     T: AsRef<Path>,
 {