Add skeptic support

This commit adds Readme testing using
[skeptic](https://github.com/brson/rust-skeptic).

Author: johannhof

.travis.yml

@@ -25,6 +25,7 @@ addons:
     - libdw-dev
 after_success:
 - travis-cargo --only stable doc-upload
+- rm tests/skeptic.rs # "skip" skeptic doctests for coverage
 - travis-cargo coveralls --no-sudo
 notifications:
   email:

Cargo.toml

@@ -8,6 +8,7 @@ license = "MIT OR Apache-2.0"
 readme = "README.md"
 documentation = "http://killercup.github.io/assert_cli/"
 description = "Test CLI Applications."
+build = "build.rs"
 
 [features]
 default = []
@@ -17,3 +18,9 @@ dev = ["clippy"]
 ansi_term = "0.6.3"
 difference = "0.4.0"
 clippy = {version = "0.0.23", optional = true}
+
+[build-dependencies]
+skeptic = "0.5"
+
+[dev-dependencies]
+skeptic = "0.5"

Readme.md

@@ -24,22 +24,28 @@ Here's a trivial example:
 
 ```rust
 extern crate assert_cli;
-assert_cli::assert_cli_output("echo", &["42"], "42").unwrap();
+fn main() {
+  assert_cli::assert_cli_output("echo", &["42"], "42").unwrap();
+}
 ```
 
 Or if you'd rather use the macro:
 
 ```rust,ignore
 #[macro_use] extern crate assert_cli;
-assert_cli!("echo", &["42"] => Success, "42").unwrap();
-assert_cli!("black-box", &["--special"] => Error 42, "error no 42\n").unwrap()
+fn main() {
+  assert_cli!("echo", &["42"] => Success, "42").unwrap();
+  assert_cli!("black-box", &["--special"] => Error 42, "error no 42\n").unwrap()
+}
 ```
 
 And here is one that will fail:
 
 ```rust,should_panic
 extern crate assert_cli;
-assert_cli::assert_cli_output("echo", &["42"], "1337").unwrap();
+fn main() {
+  assert_cli::assert_cli_output("echo", &["42"], "1337").unwrap();
+}
 ```
 
 this will show a nice, colorful diff in your terminal, like this:
@@ -53,18 +59,22 @@ If you'd prefer to not check the output:
 
 ```rust
 #[macro_use] extern crate assert_cli;
-assert_cli::assert_cli("echo", &["42"]).unwrap();
-assert_cli!("echo", &["42"] => Success).unwrap();
+fn main() {
+  assert_cli::assert_cli("echo", &["42"]).unwrap();
+  assert_cli!("echo", &["42"] => Success).unwrap();
+}
 ```
 
 All exported functions and the macro return a `Result` containing the
 `Output` of the process, allowing you to do further custom assertions:
 
 ```rust
 #[macro_use] extern crate assert_cli;
-let output = assert_cli!("echo", &["Number 42"] => Success).unwrap();
-let stdout = std::str::from_utf8(&output.stdout).unwrap();
-assert!(stdout.contains("42"));
+fn main() {
+  let output = assert_cli!("echo", &["Number 42"] => Success).unwrap();
+  let stdout = std::str::from_utf8(&output.stdout).unwrap();
+  assert!(stdout.contains("42"));
+}
 ```
 
 ## License

build.rs

@@ -0,0 +1,5 @@
+extern crate skeptic;
+
+fn main() {
+    skeptic::generate_doc_tests(&["README.md"]);
+}

tests/skeptic.rs

@@ -0,0 +1 @@
+include!(concat!(env!("OUT_DIR"), "/skeptic-tests.rs"));