Add tests for loading subscriptions file

.gitignore

@@ -1,4 +1,5 @@
 target
 *.mp3
 *.webm
-*.txt
+/subscriptions.txt
+/downloaded.txt

Cargo.lock

@@ -1017,6 +1017,7 @@ dependencies = [
  "clap",
  "reqwest",
  "scraper",
+ "tempfile",
 ]
 
 [[package]]

Cargo.toml

@@ -10,3 +10,6 @@ atom_syndication = "0.12.1"
 reqwest = { version = "0.11.18", features = ["json", "blocking"] }
 scraper = "0.17.1"
 clap = "4.3.19"
+
+[dev-dependencies]
+tempfile = "*"

src/errors.rs

@@ -1,4 +1,4 @@
-use std::{fmt::Display, string::FromUtf8Error};
+use std::{fmt::Display, str::Utf8Error, string::FromUtf8Error};
 
 #[derive(Debug)]
 pub struct Error {
@@ -9,6 +9,13 @@ impl Display for Error {
         f.write_str(self.details.to_string().as_str())
     }
 }
+impl From<Utf8Error> for Error {
+    fn from(value: Utf8Error) -> Self {
+        Self {
+            details: value.to_string(),
+        }
+    }
+}
 impl From<FromUtf8Error> for Error {
     fn from(value: FromUtf8Error) -> Self {
         Self {

src/lib.rs

@@ -21,7 +21,6 @@ pub fn run(
     fetch_download: FetchDownload,
 ) -> Result<()> {
     for channel_name in subscriptions::lines_from(subscriptions)? {
-        let channel_name = channel_name?;
         println!("Channel: {}", channel_name);
         let feed_url = feed_find(site, &channel_name)?;
         for entry in feed_get(&feed_url)?.entries() {

src/subscriptions.rs

@@ -1,10 +1,87 @@
 use crate::prelude::*;
 
 use std::fs::File;
-use std::io::{BufRead, BufReader, Lines};
+use std::io::{BufRead, BufReader};
 
-pub fn lines_from(file_name: &str) -> Result<Lines<BufReader<File>>> {
+pub fn lines_from(file_name: &str) -> Result<Vec<String>> {
     let file = File::open(file_name)?;
     let reader = BufReader::new(file);
-    Ok(reader.lines())
+    let mut lines = vec![];
+    for line in reader.lines() {
+        if let Ok(line) = line {
+            if line.starts_with('@') {
+                lines.push(line);
+            }
+        }
+    }
+    Ok(lines)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{fs::File, io::Write, str::from_utf8};
+
+    use tempfile::{tempdir, TempDir};
+
+    use super::*;
+
+    #[test]
+    fn can_load_file() -> Result<()> {
+        //given
+        let (dir, file_name) = create_text_file(
+            "subscriptions.txt",
+            include_bytes!("../test/data/subscriptions.txt"),
+        )?;
+
+        //when
+        let result = lines_from(&file_name)?;
+
+        //then
+        drop(dir);
+        assert_eq!(result, ["@sub1", "@sub2", "@sub3"]);
+        Ok(())
+    }
+
+    #[test]
+    fn ignores_blank_lines() -> Result<()> {
+        //given
+        let (dir, file_name) = create_text_file(
+            "subscriptions.txt",
+            include_bytes!("../test/data/subscriptions-blank-line.txt"),
+        )?;
+
+        //when
+        let result = lines_from(&file_name)?;
+
+        //then
+        drop(dir);
+        assert_eq!(result, ["@sub1", "@sub2", "@sub3"]);
+        Ok(())
+    }
+
+    #[test]
+    fn ignores_comments() -> Result<()> {
+        //given
+        let (dir, file_name) = create_text_file(
+            "subscriptions.txt",
+            include_bytes!("../test/data/subscriptions-comment.txt"),
+        )?;
+
+        //when
+        let result = lines_from(&file_name)?;
+
+        //then
+        drop(dir);
+        assert_eq!(result, ["@sub1", "@sub3"]);
+        Ok(())
+    }
+
+    fn create_text_file(name: &str, data: &[u8]) -> Result<(TempDir, String)> {
+        let data = from_utf8(data)?;
+        let dir = tempdir()?;
+        let filename = format!("{}", &dir.path().join(name).display());
+        let file = File::create(&filename)?;
+        write!(&file, "{data}")?;
+        Ok((dir, filename))
+    }
 }

test/data/subscriptions-blank-line.txt

@@ -0,0 +1,4 @@
+@sub1
+
+@sub2
+@sub3

test/data/subscriptions-comment.txt

@@ -0,0 +1,3 @@
+@sub1
+#@sub2
+@sub3

test/data/subscriptions.txt

@@ -0,0 +1,3 @@
+@sub1
+@sub2
+@sub3