diff --git a/.travis.yml b/.travis.yml
index a3fdd804fb8..a421a7b9334 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,6 +22,7 @@ matrix:
     - env: TARGET=x86_64-apple-darwin
            ALT=i686-apple-darwin
       os: osx
+      osx_image: xcode9.2
       if: branch != master OR type = pull_request
 
     - env: TARGET=x86_64-unknown-linux-gnu
diff --git a/tests/testsuite/metabuild.rs b/tests/testsuite/metabuild.rs
index 6420edac657..c96f0c4b6b6 100644
--- a/tests/testsuite/metabuild.rs
+++ b/tests/testsuite/metabuild.rs
@@ -2,7 +2,8 @@ use glob::glob;
 use serde_json;
 use std::str;
 use support::{
-    basic_lib_manifest, basic_manifest, project, registry::Package, rustc_host, Project,
+    basic_lib_manifest, basic_manifest, is_coarse_mtime, project, registry::Package, rustc_host,
+    Project,
 };
 
 #[test]
@@ -212,6 +213,14 @@ fn metabuild_lib_name() {
 
 #[test]
 fn metabuild_fresh() {
+    if is_coarse_mtime() {
+        // This test doesn't work on coarse mtimes very well. Because the
+        // metabuild script is created at build time, its mtime is almost
+        // always equal to the mtime of the output. The second call to `build`
+        // will then think it needs to be rebuilt when it should be fresh.
+        return;
+    }
+
     // Check that rebuild is fresh.
     let p = project()
         .file(
diff --git a/tests/testsuite/support/mod.rs b/tests/testsuite/support/mod.rs
index f9ddb5380b4..9d818070ce6 100644
--- a/tests/testsuite/support/mod.rs
+++ b/tests/testsuite/support/mod.rs
@@ -113,11 +113,12 @@ use std::os;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Output};
 use std::str;
-use std::time::Duration;
+use std::time::{self, Duration};
 use std::usize;
 
 use cargo;
 use cargo::util::{CargoResult, ProcessBuilder, ProcessError, Rustc};
+use filetime;
 use serde_json::{self, Value};
 use url::Url;
 
@@ -279,8 +280,19 @@ impl ProjectBuilder {
             self._file(Path::new("Cargo.toml"), &basic_manifest("foo", "0.0.1"))
         }
 
+        let past = time::SystemTime::now() - Duration::new(1, 0);
+        let ftime = filetime::FileTime::from_system_time(past);
+
         for file in self.files.iter() {
             file.mk();
+            if is_coarse_mtime() {
+                // Place the entire project 1 second in the past to ensure
+                // that if cargo is called multiple times, the 2nd call will
+                // see targets as "fresh". Without this, if cargo finishes in
+                // under 1 second, the second call will see the mtime of
+                // source == mtime of output and consider it dirty.
+                filetime::set_file_times(&file.path, ftime, ftime).unwrap();
+            }
         }
 
         for symlink in self.symlinks.iter() {
@@ -1510,3 +1522,11 @@ pub fn git_process(s: &str) -> ProcessBuilder {
 pub fn sleep_ms(ms: u64) {
     ::std::thread::sleep(Duration::from_millis(ms));
 }
+
+/// Returns true if the local filesystem has low-resolution mtimes.
+pub fn is_coarse_mtime() -> bool {
+    // This should actually be a test that $CARGO_TARGET_DIR is on an HFS
+    // filesystem, (or any filesystem with low-resolution mtimes). However,
+    // that's tricky to detect, so for now just deal with CI.
+    cfg!(target_os = "macos") && env::var("CI").is_ok()
+}