Add basic integration tests

Also add force option--necessary for testing but may be useful to some people
who like to live dangerously

src/lib.rs

@@ -28,6 +28,7 @@ pub struct Options {
     pub recursive: bool,
     pub clobber: bool,
     pub create: bool,
+    pub force: bool,
     pub preserve_attrs: bool,
     pub verbosity: Option<u8>,
     pub filter: HashSet<u8>,
@@ -129,7 +130,7 @@ pub fn optimize(filepath: &Path, opts: &Options) -> Result<(), String> {
     // TODO: Perform stripping
 
     let output_data = png.output();
-    if file_original_size <= output_data.len() {
+    if file_original_size <= output_data.len() && !opts.force {
         println!("File already optimized");
         return Ok(());
     }
@@ -174,13 +175,26 @@ pub fn optimize(filepath: &Path, opts: &Options) -> Result<(), String> {
             }
         }
     }
-    println!("    IDAT size = {} bytes ({} bytes decrease)",
-             png.idat_data.len(),
-             idat_original_size - png.idat_data.len());
-    println!("    file size = {} bytes ({} bytes = {:.2}% decrease)",
-             output_data.len(),
-             file_original_size - output_data.len(),
-             (file_original_size - output_data.len()) as f64 / file_original_size as f64);
+    if idat_original_size >= png.idat_data.len() {
+        println!("    IDAT size = {} bytes ({} bytes decrease)",
+                 png.idat_data.len(),
+                 idat_original_size - png.idat_data.len());
+    } else {
+        println!("    IDAT size = {} bytes ({} bytes increate)",
+                 png.idat_data.len(),
+                 png.idat_data.len() - idat_original_size);
+    }
+    if file_original_size >= output_data.len() {
+        println!("    file size = {} bytes ({} bytes = {:.2}% decrease)",
+                 output_data.len(),
+                 file_original_size - output_data.len(),
+                 (file_original_size - output_data.len()) as f64 / file_original_size as f64);
+    } else {
+        println!("    file size = {} bytes ({} bytes = {:.2}% increase)",
+                 output_data.len(),
+                 output_data.len() - file_original_size,
+                 (output_data.len() - file_original_size) as f64 / file_original_size as f64);
+    }
 
     Ok(())
 }

src/main.rs

@@ -30,6 +30,7 @@ fn main() {
         fix_errors: false,
         clobber: true,
         create: true,
+        force: false,
         preserve_attrs: false,
         verbosity: Some(0),
         filter: filter,
@@ -70,6 +71,10 @@ fn main() {
                                .help("Back up modified files")
                                .short("b")
                                .long("backup"))
+                      .arg(Arg::with_name("force")
+                               .help("Write output even if larger than the original")
+                               .short("F")
+                               .long("force"))
                       .arg(Arg::with_name("recursive")
                                .help("Recurse into subdirectories")
                                .short("r")
@@ -409,6 +414,10 @@ fn parse_opts_into_struct(matches: &ArgMatches, opts: &mut oxipng::Options) -> R
         opts.backup = true;
     }
 
+    if matches.is_present("force") {
+        opts.force = true;
+    }
+
     if matches.is_present("recursive") {
         opts.recursive = true;
     }

src/png.rs

@@ -8,7 +8,7 @@ use std::io::prelude::*;
 use std::iter::Iterator;
 use std::path::Path;
 
-#[derive(Debug)]
+#[derive(Debug,PartialEq)]
 pub enum ColorType {
     Grayscale,
     RGB,
@@ -43,7 +43,7 @@ impl ColorType {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug,PartialEq)]
 pub enum BitDepth {
     One,
     Two,

tests/oxipng.rs

@@ -0,0 +1,131 @@
+extern crate oxipng;
+
+use oxipng::png;
+use std::collections::HashSet;
+use std::fs::remove_file;
+use std::path::Path;
+use std::path::PathBuf;
+
+fn get_opts(input: &Path) -> oxipng::Options {
+    let mut filter = HashSet::new();
+    filter.insert(0);
+    filter.insert(5);
+    let mut compression = HashSet::new();
+    compression.insert(9);
+    let mut memory = HashSet::new();
+    memory.insert(9);
+    let mut strategies = HashSet::new();
+    for i in 0..4 {
+        strategies.insert(i);
+    }
+
+    oxipng::Options {
+        backup: false,
+        out_file: input.with_extension("out.png").to_owned(),
+        out_dir: None,
+        stdout: false,
+        pretend: false,
+        recursive: false,
+        fix_errors: false,
+        force: true,
+        clobber: true,
+        create: true,
+        preserve_attrs: false,
+        verbosity: Some(0),
+        filter: filter,
+        interlace: None,
+        compression: compression,
+        memory: memory,
+        strategies: strategies,
+        window: 15,
+        bit_depth_reduction: true,
+        color_type_reduction: true,
+        palette_reduction: true,
+        idat_recoding: true,
+        strip: false,
+    }
+}
+
+#[test]
+fn reduce_rgba_png() {
+    let input = PathBuf::from("tests/files/test_rgba.png");
+    let opts = get_opts(&input);
+    let output = opts.out_file.clone();
+
+    match oxipng::optimize(&input, &opts) {
+        Ok(_) => (),
+        Err(x) => panic!(x.to_owned())
+    };
+    assert!(output.exists());
+
+    let png = match png::PngData::new(&output) {
+        Ok(x) => {
+            remove_file(output).ok();
+            x
+        },
+        Err(x) => {
+            remove_file(output).ok();
+            panic!(x.to_owned())
+        },
+    };
+
+    assert!(png.ihdr_data.color_type == png::ColorType::Indexed);
+    assert!(png.ihdr_data.bit_depth == png::BitDepth::Eight);
+    assert!(png.palette.unwrap().len() == 43 * 3);
+}
+
+#[test]
+fn reduce_rgb_png() {
+    let input = PathBuf::from("tests/files/test_rgb.png");
+    let opts = get_opts(&input);
+    let output = opts.out_file.clone();
+
+    match oxipng::optimize(&input, &opts) {
+        Ok(_) => (),
+        Err(x) => panic!(x.to_owned())
+    };
+    assert!(output.exists());
+
+    let png = match png::PngData::new(&output) {
+        Ok(x) => {
+            remove_file(output).ok();
+            x
+        },
+        Err(x) => {
+            remove_file(output).ok();
+            panic!(x.to_owned())
+        },
+    };
+
+    assert!(png.ihdr_data.color_type == png::ColorType::Indexed);
+    assert!(png.ihdr_data.bit_depth == png::BitDepth::Eight);
+    assert!(png.palette.unwrap().len() == 43 * 3);
+}
+
+#[test]
+fn reduce_palette_png() {
+    let input = PathBuf::from("tests/files/test_palette.png");
+    let opts = get_opts(&input);
+    let output = opts.out_file.clone();
+
+    match oxipng::optimize(&input, &opts) {
+        Ok(_) => (),
+        Err(x) => panic!(x.to_owned())
+    };
+    assert!(output.exists());
+
+    let png = match png::PngData::new(&output) {
+        Ok(x) => {
+            remove_file(output).ok();
+            x
+        },
+        Err(x) => {
+            remove_file(output).ok();
+            panic!(x.to_owned())
+        },
+    };
+
+    assert!(png.ihdr_data.color_type == png::ColorType::Indexed);
+    assert!(png.ihdr_data.bit_depth == png::BitDepth::Eight);
+    assert!(png.palette.unwrap().len() == 43 * 3);
+}