Move the code to run test into its own module.

Loading a file and running the test in it can be separated from the
mechanics of running multiple tests and scanning directories for test
files.

cranelift/src/tools/filetest/runone.rs

@@ -0,0 +1,66 @@
+//! Run the tests in a single test file.
+
+use std::borrow::{Borrow, Cow};
+use std::path::Path;
+use std::time;
+use cretonne::ir::Function;
+use cretonne::verify_function;
+use cton_reader::parse_test;
+use utils::read_to_string;
+use filetest::{TestResult, new_subtest};
+use filetest::subtest::{SubTest, Context, Result};
+
+/// Load `path` and run the test in it.
+///
+/// If running this test causes a panic, it will propagate as normal.
+pub fn run(path: &Path) -> TestResult {
+    let started = time::Instant::now();
+    let buffer = try!(read_to_string(path).map_err(|e| e.to_string()));
+    let testfile = try!(parse_test(&buffer).map_err(|e| e.to_string()));
+    if testfile.functions.is_empty() {
+        return Err("no functions found".to_string());
+    }
+    // Parse the test commands.
+    let mut tests = try!(testfile.commands.iter().map(new_subtest).collect::<Result<Vec<_>>>());
+
+    // Sort the tests so the mutators are at the end, and those that don't need the verifier are at
+    // the front.
+    tests.sort_by_key(|st| (st.is_mutating(), st.needs_verifier()));
+
+    // Isolate the last test in the hope that this is the only mutating test.
+    // If so, we can completely avoid cloning functions.
+    let last_test = match tests.pop() {
+        None => return Err("no test commands found".to_string()),
+        Some(t) => t,
+    };
+
+    for (func, details) in testfile.functions {
+        let mut context = Context {
+            details: details,
+            verified: false,
+        };
+
+        for test in &tests {
+            try!(run_one_test(test.borrow(), Cow::Borrowed(&func), &mut context));
+        }
+        // Run the last test with an owned function which means it won't need to clone it before
+        // mutating.
+        try!(run_one_test(last_test.borrow(), Cow::Owned(func), &mut context));
+    }
+
+
+    // TODO: Actually run the tests.
+    Ok(started.elapsed())
+}
+
+fn run_one_test(test: &SubTest, func: Cow<Function>, context: &mut Context) -> Result<()> {
+    let name = format!("{}({})", test.name(), func.name);
+
+    // Should we run the verifier before this test?
+    if !context.verified && test.needs_verifier() {
+        try!(verify_function(&func).map_err(|e| e.to_string()));
+        context.verified = true;
+    }
+
+    test.run(func, context).map_err(|e| format!("{}: {}", name, e))
+}