Move colored diff output to feature flag

Cargo.toml

@@ -22,7 +22,11 @@ regex = "^1.0.5"
 lazy_static = "^1.1.0"
 serde_json = "^1.0.17"
 difference = "^2.0"
-colored = "^1.6"
+colored = { version = "^1.6", optional = true }
 log = "0.4.6"
 percent-encoding = "^1.0.1"
 assert-json-diff = "^1.0.0"
+
+[features]
+default = ["color"]
+color = ["colored"]

src/diff.rs

@@ -1,4 +1,5 @@
 use difference::{Difference, Changeset};
+#[cfg(feature = "color")]
 use colored::*;
 
 pub fn compare(expected: &str, actual: &str) -> String {
@@ -21,24 +22,40 @@ pub fn compare(expected: &str, actual: &str) -> String {
  for (i, change) in diffs.iter().enumerate() {
  match change {
  Difference::Same(ref z) => {
+ #[cfg(feature = "color")]
  result.push_str(&z.green().to_string());
+ #[cfg(not(feature = "color"))]
+ result.push_str(&z);
+
  if i < diffs.len() - 1 { result.push(' '); }
  }
  Difference::Add(ref z) => {
+ #[cfg(feature = "color")]
  result.push_str(&z.white().on_green().to_string());
+ #[cfg(not(feature = "color"))]
+ result.push_str(&z);
+
  if i < diffs.len() - 1 { result.push(' '); }
  }
  _ => (),
  }
  }
  result.push('\n');
  } else {
+ #[cfg(feature = "color")]
  result.push_str(&x.bright_green().to_string());
+ #[cfg(not(feature = "color"))]
+ result.push_str(&x);
+
  result.push('\n');
  }
  },
  Difference::Rem(ref x) => {
+ #[cfg(feature = "color")]
  result.push_str(&x.red().to_string());
+ #[cfg(not(feature = "color"))]
+ result.push_str(&x);
+
  result.push('\n');
  },
  }

src/lib.rs

@@ -135,7 +135,9 @@
 //!
 //! The errors produced by the `assert` method contain information about the tested mock, but also about the
 //! **last unmatched request**, which can be very useful to track down an error in your implementation or
-//! a missing or incomplete mock. A coloured diff is also displayed.
+//! a missing or incomplete mock. A colored diff is also displayed.
+//! 
+//! Color output is enabled by default, but can be toggled with the `color` feature flag.
 //!
 //! Here's an example of how a `Mock#assert` error looks like:
 //!
@@ -155,7 +157,7 @@
 //!
 //! > Difference:
 //!
-//! # A coloured diff
+//! # A colored diff
 //!
 //! ```
 //!
@@ -470,6 +472,7 @@ extern crate regex;
 #[macro_use] extern crate log;
 extern crate serde_json;
 extern crate difference;
+#[cfg(feature = "color")]
 extern crate colored;
 extern crate percent_encoding;
 extern crate assert_json_diff;