diff --git a/src/libstd/dynamic_lib.rs b/src/libstd/dynamic_lib.rs
index bc71f8ae790..ed8ff821f5c 100644
--- a/src/libstd/dynamic_lib.rs
+++ b/src/libstd/dynamic_lib.rs
@@ -183,7 +183,7 @@ mod test {
         let expected_result = 1.0;
         let result = cosine(argument);
         if result != expected_result {
-            fail!("cos({:?}) != {:?} but equaled {:?} instead", argument,
+            fail!("cos({}) != {} but equaled {} instead", argument,
                    expected_result, result)
         }
     }
diff --git a/src/libstd/io/fs.rs b/src/libstd/io/fs.rs
index e8fed67fffe..8632fc63e52 100644
--- a/src/libstd/io/fs.rs
+++ b/src/libstd/io/fs.rs
@@ -963,7 +963,7 @@ mod test {
 
     macro_rules! error( ($e:expr, $s:expr) => (
         match $e {
-            Ok(val) => fail!("Should have been an error, was {:?}", val),
+            Ok(val) => fail!("Unexpected success. Should've been: {}", $s),
             Err(ref err) => assert!(err.to_string().as_slice().contains($s.as_slice()),
                                     format!("`{}` did not contain `{}`", err, $s))
         }
diff --git a/src/libstd/io/net/pipe.rs b/src/libstd/io/net/pipe.rs
index 3f8069468f6..e0cf761fdbd 100644
--- a/src/libstd/io/net/pipe.rs
+++ b/src/libstd/io/net/pipe.rs
@@ -340,7 +340,7 @@ mod tests {
                         assert!(e.kind == BrokenPipe ||
                                 e.kind == NotConnected ||
                                 e.kind == ConnectionReset,
-                                "unknown error {:?}", e);
+                                "unknown error {}", e);
                         break;
                     }
                 }
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index 03eca5c728b..e758dec6bff 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -1975,7 +1975,7 @@ mod tests {
         let path = os::self_exe_name();
         assert!(path.is_some());
         let path = path.unwrap();
-        debug!("{:?}", path.clone());
+        debug!("{}", path.display());
 
         // Hard to test this function
         assert!(path.is_absolute());
@@ -1986,7 +1986,7 @@ mod tests {
         let path = os::self_exe_path();
         assert!(path.is_some());
         let path = path.unwrap();
-        debug!("{:?}", path.clone());
+        debug!("{}", path.display());
 
         // Hard to test this function
         assert!(path.is_absolute());
@@ -1999,7 +1999,7 @@ mod tests {
         assert!(e.len() > 0u);
         for p in e.iter() {
             let (n, v) = (*p).clone();
-            debug!("{:?}", n.clone());
+            debug!("{}", n);
             let v2 = getenv(n.as_slice());
             // MingW seems to set some funky environment variables like
             // "=C:=C:\MinGW\msys\1.0\bin" and "!::=::\" that are returned
@@ -2037,8 +2037,8 @@ mod tests {
         let cwd = getcwd();
         debug!("Current working directory: {}", cwd.display());
 
-        debug!("{:?}", make_absolute(&Path::new("test-path")));
-        debug!("{:?}", make_absolute(&Path::new("/usr/bin")));
+        debug!("{}", make_absolute(&Path::new("test-path")).display());
+        debug!("{}", make_absolute(&Path::new("/usr/bin")).display());
     }
 
     #[test]
diff --git a/src/libstd/path/posix.rs b/src/libstd/path/posix.rs
index 27eafdab642..69b6dd76676 100644
--- a/src/libstd/path/posix.rs
+++ b/src/libstd/path/posix.rs
@@ -986,19 +986,19 @@ mod tests {
                         let path = $path;
                         let filename = $filename;
                         assert!(path.filename_str() == filename,
-                                "{}.filename_str(): Expected `{:?}`, found {:?}",
+                                "{}.filename_str(): Expected `{}`, found {}",
                                 path.as_str().unwrap(), filename, path.filename_str());
                         let dirname = $dirname;
                         assert!(path.dirname_str() == dirname,
-                                "`{}`.dirname_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.dirname_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), dirname, path.dirname_str());
                         let filestem = $filestem;
                         assert!(path.filestem_str() == filestem,
-                                "`{}`.filestem_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.filestem_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), filestem, path.filestem_str());
                         let ext = $ext;
                         assert!(path.extension_str() == mem::transmute(ext),
-                                "`{}`.extension_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.extension_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), ext, path.extension_str());
                     }
                 }
@@ -1200,11 +1200,11 @@ mod tests {
                     let comps = path.components().collect::<Vec<&[u8]>>();
                     let exp: &[&str] = $exp;
                     let exps = exp.iter().map(|x| x.as_bytes()).collect::<Vec<&[u8]>>();
-                    assert!(comps == exps, "components: Expected {:?}, found {:?}",
+                    assert!(comps == exps, "components: Expected {}, found {}",
                             comps, exps);
                     let comps = path.components().rev().collect::<Vec<&[u8]>>();
                     let exps = exps.into_iter().rev().collect::<Vec<&[u8]>>();
-                    assert!(comps == exps, "rev_components: Expected {:?}, found {:?}",
+                    assert!(comps == exps, "rev_components: Expected {}, found {}",
                             comps, exps);
                 }
             );
diff --git a/src/libstd/path/windows.rs b/src/libstd/path/windows.rs
index 5bd738ed58b..4456cf96094 100644
--- a/src/libstd/path/windows.rs
+++ b/src/libstd/path/windows.rs
@@ -996,7 +996,7 @@ pub fn is_sep_byte_verbatim(u: &u8) -> bool {
 }
 
 /// Prefix types for Path
-#[deriving(PartialEq, Clone)]
+#[deriving(PartialEq, Clone, Show)]
 pub enum PathPrefix {
     /// Prefix `\\?\`, uint is the length of the following component
     VerbatimPrefix(uint),
@@ -1172,7 +1172,7 @@ mod tests {
                     let exp = $exp;
                     let res = parse_prefix(path);
                     assert!(res == exp,
-                            "parse_prefix(\"{}\"): expected {:?}, found {:?}", path, exp, res);
+                            "parse_prefix(\"{}\"): expected {}, found {}", path, exp, res);
                 }
             )
         )
@@ -1904,19 +1904,19 @@ mod tests {
                         let path = $path;
                         let filename = $filename;
                         assert!(path.filename_str() == filename,
-                                "`{}`.filename_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.filename_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), filename, path.filename_str());
                         let dirname = $dirname;
                         assert!(path.dirname_str() == dirname,
-                                "`{}`.dirname_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.dirname_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), dirname, path.dirname_str());
                         let filestem = $filestem;
                         assert!(path.filestem_str() == filestem,
-                                "`{}`.filestem_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.filestem_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), filestem, path.filestem_str());
                         let ext = $ext;
                         assert!(path.extension_str() == mem::transmute(ext),
-                                "`{}`.extension_str(): Expected `{:?}`, found `{:?}`",
+                                "`{}`.extension_str(): Expected `{}`, found `{}`",
                                 path.as_str().unwrap(), ext, path.extension_str());
                     }
                 }
@@ -1974,16 +1974,16 @@ mod tests {
                     let path = Path::new($path);
                     let (abs, vol, cwd, rel) = ($abs, $vol, $cwd, $rel);
                     let b = path.is_absolute();
-                    assert!(b == abs, "Path '{}'.is_absolute(): expected {:?}, found {:?}",
+                    assert!(b == abs, "Path '{}'.is_absolute(): expected {}, found {}",
                             path.as_str().unwrap(), abs, b);
                     let b = is_vol_relative(&path);
-                    assert!(b == vol, "is_vol_relative('{}'): expected {:?}, found {:?}",
+                    assert!(b == vol, "is_vol_relative('{}'): expected {}, found {}",
                             path.as_str().unwrap(), vol, b);
                     let b = is_cwd_relative(&path);
-                    assert!(b == cwd, "is_cwd_relative('{}'): expected {:?}, found {:?}",
+                    assert!(b == cwd, "is_cwd_relative('{}'): expected {}, found {}",
                             path.as_str().unwrap(), cwd, b);
                     let b = path.is_relative();
-                    assert!(b == rel, "Path '{}'.is_relativf(): expected {:?}, found {:?}",
+                    assert!(b == rel, "Path '{}'.is_relativf(): expected {}, found {}",
                             path.as_str().unwrap(), rel, b);
                 }
             )
@@ -2016,7 +2016,7 @@ mod tests {
                     let exp = $exp;
                     let res = path.is_ancestor_of(&dest);
                     assert!(res == exp,
-                            "`{}`.is_ancestor_of(`{}`): Expected {:?}, found {:?}",
+                            "`{}`.is_ancestor_of(`{}`): Expected {}, found {}",
                             path.as_str().unwrap(), dest.as_str().unwrap(), exp, res);
                 }
             )
@@ -2151,7 +2151,7 @@ mod tests {
                     let res = path.path_relative_from(&other);
                     let exp = $exp;
                     assert!(res.as_ref().and_then(|x| x.as_str()) == exp,
-                            "`{}`.path_relative_from(`{}`): Expected {:?}, got {:?}",
+                            "`{}`.path_relative_from(`{}`): Expected {}, got {}",
                             path.as_str().unwrap(), other.as_str().unwrap(), exp,
                             res.as_ref().and_then(|x| x.as_str()));
                 }