Run the filetests as part of "cargo test".

Refactor the filetests harness so that it can be run as part of
`cargo test`. And begin reorganizing the test harness code in preparation
for moving it out of the src directory.
 - Test subcommand files are now named `test_*.rs`.
 - cton-util subcommand files now just export their `run` and nothing else.
 - src/filetest/mod.rs now also just exports `run` and nothing else.
 - Tests are now run in release mode (with debug assertions enabled).

cranelift/src/cat.rs

@@ -3,12 +3,9 @@
 //! Read a sequence of Cretonne IL files and print them again to stdout. This has the effect of
 //! normalizing formatting and removing comments.
 
-use std::borrow::Cow;
-use cretonne::ir::Function;
-use cton_reader::{parse_functions, TestCommand};
+use cton_reader::parse_functions;
 use CommandResult;
 use utils::read_to_string;
-use filetest::subtest::{self, SubTest, Context, Result as STResult};
 
 pub fn run(files: Vec<String>) -> CommandResult {
     for (i, f) in files.into_iter().enumerate() {
@@ -37,34 +34,3 @@ fn cat_one(filename: String) -> CommandResult {
 
     Ok(())
 }
-
-/// Object implementing the `test cat` sub-test.
-///
-/// This command is used for testing the parser and function printer. It simply parses a function
-/// and prints it out again.
-///
-/// The result is verified by filecheck.
-struct TestCat;
-
-pub fn subtest(parsed: &TestCommand) -> STResult<Box<SubTest>> {
-    assert_eq!(parsed.command, "cat");
-    if !parsed.options.is_empty() {
-        Err(format!("No options allowed on {}", parsed))
-    } else {
-        Ok(Box::new(TestCat))
-    }
-}
-
-impl SubTest for TestCat {
-    fn name(&self) -> Cow<str> {
-        Cow::from("cat")
-    }
-
-    fn needs_verifier(&self) -> bool {
-        false
-    }
-
-    fn run(&self, func: Cow<Function>, context: &Context) -> STResult<()> {
-        subtest::run_filecheck(&func.display(context.isa).to_string(), context)
-    }
-}