add support for convenient testing

README.md

@@ -15,6 +15,7 @@ yes, this too tries to cache everything it gets from Advent of Code to spare the
 
 ```rust
 use aocd::*;
+// or, if you prefer: use aocd::prelude::*;
 
 #[aocd(2022, 1)]
 fn main() {
@@ -29,14 +30,29 @@ fn main() {
 }
 ```
 
+### Testing
+
+If you want to use a smaller test input while debugging, this can be done by just adding the file name at the top.
+In this case, the `input!` macro simply reads the file, and `submit!` just prints the result without submitting to AoC.
+
+```rust
+use aocd::*;
+
+#[aocd(2022, 1, "test.txt")]
+fn main() {
+    ...
+}
+```
+
+
 ## Quickstart
 
 You need to provide your AoC session token in order for this crate to get your personal puzzle input and to be able to
 submit answers for you. This is a cookie which is set when you login to AoC. You can find it with your browser
 inspector. See [this issue](https://github.com/wimglenn/advent-of-code/issues/1) for a how-to. You can provide it to
 `aocd` using any of the following alternatives:
 
-```bash
+``` bash
 # Alt 1 (this way doesn't require any environment variables to be set):
 mkdir -p ~/.config/aocd
 echo "your session cookie here" > ~/.config/aocd/token

src/client.rs

@@ -10,6 +10,7 @@ pub struct Aocd {
     url: String,
     session_token: String,
     cache: cache::Cache,
+    test_file: Option<String>,
 }
 
 impl Aocd {
@@ -18,10 +19,21 @@ impl Aocd {
     /// Requires a valid session cookie from adventofcode.com to be in a file named `~/.config/aocd/token`
     /// It will also require write access to `~/.cache/aocd` to cache puzzle inputs and answers.
     ///
+    /// Alternatively, if a test file is provided, the client will just be a thin wrapper using the
+    /// file as input and simply printing answers to stdout.
+    ///
+    /// # Examples
+    /// ```
+    /// use aocd::Aocd;
+    ///
+    /// let client = Aocd::new(2020, 1, None);
+    /// let test_client = Aocd::new(2020, 1, Some("test_input.txt"));
+    /// ```
+    ///
     /// # Panics
     /// Panics if the session cookie is not found or the cache could not be successfully setup/initialized.
     #[must_use]
-    pub fn new(year: u16, day: u8) -> Self {
+    pub fn new(year: u16, day: u8, test_file: Option<&str>) -> Self {
         let session_token = find_aoc_token();
         let cache = cache::Cache::new(year, day, &session_token)
             .expect("Should be able to create cache for aocd");
@@ -37,6 +49,7 @@ impl Aocd {
             url,
             session_token,
             cache,
+            test_file: test_file.map(|s| s.to_string()),
         }
     }
 
@@ -48,6 +61,14 @@ impl Aocd {
     /// Panics if the Advent of Code server responds with an error.
     #[must_use]
     pub fn get_input(&self) -> String {
+        if let Some(test_file) = &self.test_file {
+            return std::fs::read_to_string(test_file)
+                .expect("Failed to read test file")
+                .trim_end_matches('\n')
+                .trim_end_matches('\r')
+                .to_string();
+        }
+
         if let Ok(input) = self.cache.get_input() {
             return input;
         }
@@ -74,6 +95,12 @@ impl Aocd {
     /// Panics if the Advent of Code server responds to the submission with an error.
     pub fn submit(&self, part: u8, answer: impl Display) {
         let answer = answer.to_string();
+
+        if self.test_file.is_some() {
+            println!("🕵️ Part {part} test result: {answer} 🕵️");
+            return;
+        }
+
         // First check if we have already cached a _correct_ answer for this puzzle.
         if let Ok(correct_answer) = self.cache.get_correct_answer(part) {
             if correct_answer == answer {
@@ -264,7 +291,7 @@ mod tests {
                     ("AOC_CACHE_DIR", Some(cache_path.to_str().unwrap())),
                 ],
                 move || {
-                    let client = Aocd::new(self.year, self.day);
+                    let client = Aocd::new(self.year, self.day, None);
                     if let Some(input) = &self.input {
                         let url = format!("/{}/day/{}/input", client.year, client.day);
                         let m = mock("GET", url.as_str())

src/lib.rs

@@ -1,3 +1,5 @@
+#![doc = include_str!("../README.md")]
+
 mod cache;
 mod client;