diff --git a/src/assert.rs b/src/assert.rs
index 8e8daf7..aa11a77 100644
--- a/src/assert.rs
+++ b/src/assert.rs
@@ -31,8 +31,14 @@ impl default::Default for Assert {
     /// Defaults to asserting _successful_ execution.
     fn default() -> Self {
         Assert {
-            cmd: vec!["cargo", "run", "--quiet", "--"]
-                .into_iter()
+            cmd: vec![
+                "cargo",
+                "run",
+                #[cfg(not(debug_assertions))]
+                "--release",
+                "--quiet",
+                "--",
+            ].into_iter()
                 .map(OsString::from)
                 .collect(),
             env: Environment::inherit(),
@@ -61,6 +67,8 @@ impl Assert {
             cmd: vec![
                 OsStr::new("cargo"),
                 OsStr::new("run"),
+                #[cfg(not(debug_assertions))]
+                OsStr::new("--release"),
                 OsStr::new("--quiet"),
                 OsStr::new("--bin"),
                 name.as_ref(),
@@ -530,6 +538,52 @@ mod test {
         Assert::command(&["printenv"])
     }
 
+    #[test]
+    fn main_binary_default_uses_active_profile() {
+        let assert = Assert::main_binary();
+
+        let expected = if cfg!(debug_assertions) {
+            OsString::from("cargo run --quiet -- ")
+        } else {
+            OsString::from("cargo run --release --quiet -- ")
+        };
+
+        assert_eq!(
+            expected,
+            assert
+                .cmd
+                .into_iter()
+                .fold(OsString::from(""), |mut cmd, token| {
+                    cmd.push(token);
+                    cmd.push(" ");
+                    cmd
+                })
+        );
+    }
+
+    #[test]
+    fn cargo_binary_default_uses_active_profile() {
+        let assert = Assert::cargo_binary("hello");
+
+        let expected = if cfg!(debug_assertions) {
+            OsString::from("cargo run --quiet --bin hello -- ")
+        } else {
+            OsString::from("cargo run --release --quiet --bin hello -- ")
+        };
+
+        assert_eq!(
+            expected,
+            assert
+                .cmd
+                .into_iter()
+                .fold(OsString::from(""), |mut cmd, token| {
+                    cmd.push(token);
+                    cmd.push(" ");
+                    cmd
+                })
+        );
+    }
+
     #[test]
     fn take_ownership() {
         let x = Environment::inherit();
diff --git a/src/bin/assert_fixture.rs b/src/bin/assert_fixture.rs
index 5651c8f..66a0fb4 100644
--- a/src/bin/assert_fixture.rs
+++ b/src/bin/assert_fixture.rs
@@ -1,8 +1,8 @@
 extern crate failure;
 
+use std::env;
 use std::io;
 use std::io::Write;
-use std::env;
 use std::process;
 
 use failure::ResultExt;
diff --git a/src/output.rs b/src/output.rs
index ee91c89..01a4473 100644
--- a/src/output.rs
+++ b/src/output.rs
@@ -5,8 +5,8 @@ use std::rc;
 use difference::Changeset;
 use failure;
 
-use errors::*;
 use diff;
+use errors::*;
 
 #[derive(Clone, PartialEq, Eq)]
 pub enum Content {