diff --git a/src/test/run-pass/exponential-notation.rs b/src/test/run-pass/exponential-notation.rs
new file mode 100644
index 0000000000000..254c093e703a3
--- /dev/null
+++ b/src/test/run-pass/exponential-notation.rs
@@ -0,0 +1,34 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[feature(macro_rules)];
+
+use s = std::num::strconv;
+use to_str = std::num::strconv::float_to_str_common;
+
+macro_rules! t(($a:expr, $b:expr) => { { let (r, _) = $a; assert_eq!(r, $b.to_owned()) } })
+
+pub fn main() {
+    // Basic usage
+    t!(to_str(1.2345678e-5, 10u, true, s::SignNeg, s::DigMax(6), s::ExpDec, false),
+             "1.234568e-5")
+
+    // Hexadecimal output
+    t!(to_str(7.281738281250e+01, 16u, true, s::SignAll, s::DigMax(6), s::ExpBin, false),
+              "+1.2345p+6")
+    t!(to_str(-1.777768135071e-02, 16u, true, s::SignAll, s::DigMax(6), s::ExpBin, false),
+             "-1.2345p-6")
+
+    // Some denormals
+    t!(to_str(4.9406564584124654e-324, 10u, true, s::SignNeg, s::DigMax(6), s::ExpBin, false),
+             "1p-1074")
+    t!(to_str(2.2250738585072009e-308, 10u, true, s::SignNeg, s::DigMax(6), s::ExpBin, false),
+             "1p-1022")
+}
diff --git a/src/test/run-pass/ifmt.rs b/src/test/run-pass/ifmt.rs
index 76759d04ab4ae..610cba1eb1fa6 100644
--- a/src/test/run-pass/ifmt.rs
+++ b/src/test/run-pass/ifmt.rs
@@ -1,4 +1,4 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -219,6 +219,14 @@ pub fn main() {
     t!(format!("{:+10.3f}", 1.0f64),  "    +1.000");
     t!(format!("{:+10.3f}", -1.0f64), "    -1.000");
 
+    t!(format!("{:e}", 1.2345e6f32), "1.2345e6");
+    t!(format!("{:e}", 1.2345e6f64), "1.2345e6");
+    t!(format!("{:E}", 1.2345e6f64), "1.2345E6");
+    t!(format!("{:.3e}", 1.2345e6f64), "1.234e6");
+    t!(format!("{:10.3e}", 1.2345e6f64),   "   1.234e6");
+    t!(format!("{:+10.3e}", 1.2345e6f64),  "  +1.234e6");
+    t!(format!("{:+10.3e}", -1.2345e6f64), "  -1.234e6");
+
     // Escaping
     t!(format!("\\{"), "{");
     t!(format!("\\}"), "}");