Hulto eldritch file append (#4)

* eldritch append works + testing

* Remove file after test. Added docs.

* Missed append. Removing test file.

* Added test existing.

* Update README.md

* Removed uneeded match case.

* Update eldritch_nav.yml

Co-authored-by: Nicholas OBrien <ndo9903@rit.edu>

cmd/implants/eldritch/README.md

@@ -0,0 +1,10 @@
+# Build 
+```
+cd ./cmd/implants/eldritch/
+cargo build
+```
+# Test 
+```
+cd ./cmd/implants/eldritch/
+cargo test
+```

cmd/implants/eldritch/src/file/append_impl.rs

@@ -1,5 +1,78 @@
 use anyhow::Result;
+use std::fs::OpenOptions;
+use std::io::prelude::*;
 
-pub fn append(_path: String, _content: String) -> Result<()> {
-    unimplemented!("Method unimplemented")
-}
+
+pub fn append(path: String, content: String) -> Result<()> {
+    let mut file = OpenOptions::new()
+        .create(true) //Do we want to create the file if it doesn't exist? - Yes!
+        .write(true)    
+        .append(true)
+        .open(path)?;
+
+    writeln!(file, "{}", content)?;
+    Ok(())
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::io::BufReader;
+    use std::fs::File;
+    use std::fs::remove_file;
+
+    #[test]
+    fn test_append_nonexisting() -> anyhow::Result<()> {
+        //Remove the test file
+        let _ = remove_file(String::from("/tmp/win"));
+        // Run  our code
+        append(String::from("/tmp/win"), String::from("Hi2!"))?;
+        // Read the file
+        let file = BufReader::new(File::open("/tmp/win").unwrap());
+        // Reverse the file lines
+        let mut lines: Vec<_> = file.lines().map(|line| { line.unwrap() }).collect();
+        lines.reverse();
+
+        //Make sure not empty
+        assert_eq!((lines.len() > 0), true);
+
+        // Make sure the last line equals == Hi2!
+        for line in lines.iter() {
+            println!("{}", line);
+            assert_eq!(line, "Hi2!");
+            // Last line so just break.
+            break;
+        }
+        remove_file(String::from("/tmp/win"))?;
+        Ok(())
+    }    
+    #[test]
+    fn test_append_existing() -> anyhow::Result<()> {
+        //Remove the test file
+        let _remove_res = remove_file(String::from("/tmp/win"));
+        let mut file = File::create("/tmp/win").unwrap();
+        file.write_all(b"Hello, world!\n")?;
+
+        // Run  our code
+        append(String::from("/tmp/win"), String::from("Hi2!"))?;
+        // Read the file
+        let file = BufReader::new(File::open("/tmp/win").unwrap());
+        // Reverse the file lines
+        let mut lines: Vec<_> = file.lines().map(|line| { line.unwrap() }).collect();
+        lines.reverse();
+
+        //Make sure not empty
+        assert_eq!((lines.len() > 0), true);
+
+        // Make sure the last line equals == Hi2!
+        for line in lines.iter() {
+            println!("{}", line);
+            assert_eq!(line, "Hi2!");
+            // Last line so just break.
+            break;
+        }
+        remove_file(String::from("/tmp/win"))?;
+        Ok(())
+    }
+}

docs/_data/eldritch_nav.yml

@@ -12,7 +12,7 @@
         - name: "file.append"
           signature: "file.append(path: str, content: str) -> None"
           link: stdlib_file_append
-          content: The <b>file.append</b> method is very cool, and will be even cooler when Nick documents it.
+          content: The <b>file.append</b> Append content str to file at path. If no file exists at path create the file with the contents content.
         - name: "file.copy"
           signature: "file.copy(src: str, dst: str) -> None"
           link: stdlib_file_copy
@@ -105,4 +105,4 @@
 - name: Dev Docs
   link: dev
   content: I'm sure Nick would love help developing the language, but until he finishes this documentation he probably won't receive any.
-
+