Add tests for CLI behavior

This caught a bug! Parse errors should be printed to stderr, not stdout.

src/bin/cargo-deadlinks.rs

@@ -95,7 +95,7 @@ fn main() {
     let args: MainArgs = match parse_args() {
         Ok(args) => args,
         Err(err) => {
-            println!("error: {}", err);
+            eprintln!("error: {}", err);
             std::process::exit(1)
         }
     };

tests/broken_links/hardcoded-target/index.html

@@ -0,0 +1 @@
+<a href="./x.html"></a>

tests/cli_args/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "cli_args"
+version = "0.1.0"
+authors = ["Joshua Nelson <jyn514@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

tests/cli_args/src/lib.rs

@@ -0,0 +1,2 @@
+//! Links to [Private]
+struct Private;

tests/simple_project.rs

@@ -2,7 +2,7 @@ extern crate assert_cmd;
 extern crate predicates;
 
 use assert_cmd::prelude::*;
-use predicate::str::contains;
+use predicate::str::{contains, starts_with};
 use predicates::prelude::*;
 use std::env;
 use std::path::Path;
@@ -142,3 +142,69 @@ mod workspace {
         assert_doc("./tests/workspace", &[]).success();
     }
 }
+
+mod cli_args {
+    use super::*;
+
+    #[test]
+    fn it_passes_arguments_through_to_cargo() {
+        remove_all("./tests/cli_args/target");
+        deadlinks()
+            .current_dir("./tests/cli_args")
+            .arg("--")
+            .arg("--document-private-items")
+            .assert()
+            .success();
+        assert!(Path::new("./tests/cli_args/target/doc/cli_args/struct.Private.html").exists());
+    }
+
+    #[test]
+    fn it_exits_with_success_on_info_queries() {
+        for arg in &["-h", "--help", "-V", "--version"] {
+            deadlinks().arg(arg).assert().success();
+        }
+    }
+
+    #[test]
+    fn dir_works() {
+        deadlinks()
+            .arg("--dir")
+            .arg("./tests/broken_links/hardcoded-target")
+            .assert()
+            .failure()
+            .stdout(contains("Found invalid urls"));
+    }
+
+    #[test]
+    fn missing_deadlinks_gives_helpful_error() {
+        Command::cargo_bin("cargo-deadlinks")
+            .unwrap()
+            .assert()
+            .failure()
+            .stderr(contains("should be run as `cargo deadlinks`"));
+    }
+
+    #[test]
+    fn too_many_args_is_an_error() {
+        deadlinks()
+            .arg("x")
+            .assert()
+            .failure()
+            .stderr(contains("error:").and(contains("x")));
+    }
+
+    #[test]
+    fn version_contains_binary_name() {
+        Command::cargo_bin("deadlinks")
+            .unwrap()
+            .arg("--version")
+            .assert()
+            .stdout(starts_with("deadlinks "));
+        Command::cargo_bin("cargo-deadlinks")
+            .unwrap()
+            .arg("deadlinks")
+            .arg("--version")
+            .assert()
+            .stdout(starts_with("cargo-deadlinks "));
+    }
+}

tests/simple_project/src/lib.rs

@@ -8,10 +8,3 @@ pub fn bar() {}
 
 /// [Correct link](crate::bar)
 pub struct Tmp {}
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
-}