diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index adf73fb..dc4d72c 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -2,9 +2,9 @@ name: Rust
 
 on:
   push:
-    branches: [ master ]
+    branches: [master]
   pull_request:
-    branches: [ master ]
+    branches: [master]
 jobs:
   build-unix:
     runs-on: ${{ matrix.os }}-latest
@@ -13,10 +13,10 @@ jobs:
         channel: [stable, beta, nightly]
         os: [ubuntu, macos]
     steps:
-    - uses: actions/checkout@v2
-    - run: rustup default ${{ matrix.channel }}
-    - run: cargo build --verbose --all-targets
-    - run: cargo test
+      - uses: actions/checkout@v2
+      - run: rustup default ${{ matrix.channel }}
+      - run: cargo build --verbose --all-targets
+      - run: cargo test
   build-windows:
     runs-on: windows-latest
     strategy:
@@ -31,13 +31,16 @@ jobs:
           - arch: i686
             variant: gnu
     steps:
-    - uses: actions/checkout@v2
-    - run: choco install msys2
-      if: matrix.variant == 'gnu'
-    - run: rustup default ${{ matrix.channel }}
-    - run: rustup target add ${{ matrix.arch }}-pc-windows-${{ matrix.variant }}
-    - name: Build
-      run: cargo build --verbose --target ${{ matrix.arch }}-pc-windows-${{ matrix.variant }}
-    - name: Run tests
-      if: matrix.arch != 'aarch64'
-      run: cargo test --verbose --target ${{ matrix.arch }}-pc-windows-${{ matrix.variant }}
+      - uses: actions/checkout@v2
+      - run: choco install msys2
+        if: matrix.variant == 'gnu'
+      - run: rustup default ${{ matrix.channel }}
+      - run: rustup target add ${{ matrix.arch }}-pc-windows-${{ matrix.variant }}
+      - name: Build
+        run: cargo build --verbose --target ${{ matrix.arch }}-pc-windows-${{ matrix.variant }}
+      - name: Run tests (nightly)
+        if: (matrix.arch != 'aarch64') && (matrix.channel == 'nightly')
+        run: cargo test --verbose --target ${{ matrix.arch }}-pc-windows-${{ matrix.variant }} --features nightly
+      - name: Run tests
+        if: (matrix.arch != 'aarch64') && (matrix.channel != 'nightly')
+        run: cargo test --verbose --target ${{ matrix.arch }}-pc-windows-${{ matrix.variant }}
diff --git a/Cargo.toml b/Cargo.toml
index 3e11e09..d8dd7f4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,8 @@
 [package]
-authors = ["Erin P. <xampprocky@gmail.com>", "Robert C. <robertc@robertcollins.net>"]
+authors = [
+  "Erin P. <xampprocky@gmail.com>",
+  "Robert C. <robertc@robertcollins.net>",
+]
 categories = ["filesystem"]
 description = "A safe, reliable implementation of remove_dir_all for Windows"
 edition = "2018"
@@ -17,11 +20,24 @@ readme = "README.md"
 repository = "https://github.com/XAMPPRocky/remove_dir_all.git"
 version = "0.7.1-alpha.0"
 
+[features]
+default = []
+nightly = []
+
+[dependencies]
+cfg-if = "1.0.0"
+
 [target.'cfg(windows)'.dependencies]
 log = "0.4.11"
 num_cpus = "1.13"
 rayon = "1.4"
-winapi = {version = "0.3", features = ["std", "errhandlingapi", "winerror", "fileapi", "winbase"]}
+winapi = { version = "0.3", features = [
+  "std",
+  "errhandlingapi",
+  "winerror",
+  "fileapi",
+  "winbase",
+] }
 
 [target.'cfg(not(windows))'.dependencies]
 libc = "0.2"
diff --git a/src/lib.rs b/src/lib.rs
index eedbe41..6b5ac90 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,6 +6,7 @@
 //! It also provides `remove_dir_contents` and `ensure_empty_dir`
 //! for both Unix and Windows.
 
+#![cfg_attr(feature = "nightly", feature(io_error_more))]
 #![deny(missing_debug_implementations)]
 #![deny(missing_docs)]
 #![deny(rust_2018_idioms)]
diff --git a/src/portable.rs b/src/portable.rs
index 11f4deb..4ffb7c7 100644
--- a/src/portable.rs
+++ b/src/portable.rs
@@ -1,11 +1,13 @@
 use std::io;
 use std::path::Path;
 
-#[cfg(windows)]
-use crate::fs::_remove_dir_contents;
-
-#[cfg(not(windows))]
-use crate::unix::_remove_dir_contents;
+cfg_if::cfg_if! {
+    if #[cfg(windows)] {
+        use crate::fs::_remove_dir_contents;
+    } else {
+        use crate::unix::_remove_dir_contents;
+    }
+}
 
 /// Deletes the contents of `path`, but not the directory iteself.
 ///
@@ -28,26 +30,47 @@ pub fn remove_dir_contents<P: AsRef<Path>>(path: P) -> io::Result<()> {
 /// a symlink to one).
 pub fn ensure_empty_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
     match std::fs::create_dir(&path) {
-        Err(e) if e.kind() == io::ErrorKind::AlreadyExists
-            => remove_dir_contents(path),
+        Err(e) if e.kind() == io::ErrorKind::AlreadyExists => remove_dir_contents(path),
         otherwise => otherwise,
     }
 }
 
 #[cfg(test)]
 mod test {
+    use std::fs::{self, File};
+    use std::io;
+    use std::path::PathBuf;
+
     use tempfile::TempDir;
+
+    use crate::ensure_empty_dir;
     use crate::remove_dir_all;
     use crate::remove_dir_contents;
-    use crate::ensure_empty_dir;
-    use std::fs::{self, File};
-    use std::path::PathBuf;
-    use std::io;
 
-    fn expect_failure<T>(k: io::ErrorKind, r: io::Result<T>) -> io::Result<()> {
+    cfg_if::cfg_if! {
+        if #[cfg(windows)] {
+            const ENOTDIR:i32 = winapi::shared::winerror::ERROR_DIRECTORY as i32;
+            const ENOENT:i32 = winapi::shared::winerror::ERROR_FILE_NOT_FOUND as i32;
+        } else {
+            const ENOTDIR:i32 = libc::ENOTDIR;
+            const ENOENT:i32 = libc::ENOENT;
+        }
+    }
+
+    /// Expect a particular sort of failure
+    fn expect_failure<T>(n: &[i32], r: io::Result<T>) -> io::Result<()> {
         match r {
-            Err(e) if e.kind() == k => Ok(()),
-            Err(e) => Err(e),
+            Err(e)
+                if n.iter()
+                    .map(|n| Option::Some(*n))
+                    .any(|n| n == e.raw_os_error()) =>
+            {
+                Ok(())
+            }
+            Err(e) => {
+                println!("{e} {:?}, {:?}, {:?}", e.raw_os_error(), e.kind(), n);
+                Err(e)
+            }
             Ok(_) => Err(io::Error::new(
                 io::ErrorKind::Other,
                 "unexpected success".to_string(),
@@ -61,6 +84,7 @@ mod test {
         file: PathBuf,
     }
 
+    /// Create test setup: t.mkdir/file all in a tempdir.
     fn prep() -> Result<Prep, io::Error> {
         let tmp = TempDir::new()?;
         let ours = tmp.path().join("t.mkdir");
@@ -68,21 +92,25 @@ mod test {
         fs::create_dir(&ours)?;
         File::create(&file)?;
         File::open(&file)?;
-        Ok(Prep { _tmp: tmp, ours, file })
+        Ok(Prep {
+            _tmp: tmp,
+            ours,
+            file,
+        })
     }
 
     #[test]
     fn mkdir_rm() -> Result<(), io::Error> {
         let p = prep()?;
 
-        expect_failure(io::ErrorKind::Other, remove_dir_contents(&p.file))?;
+        expect_failure(&[ENOTDIR], remove_dir_contents(&p.file))?;
 
         remove_dir_contents(&p.ours)?;
-        expect_failure(io::ErrorKind::NotFound, File::open(&p.file))?;
+        expect_failure(&[ENOENT], File::open(&p.file))?;
 
         remove_dir_contents(&p.ours)?;
         remove_dir_all(&p.ours)?;
-        expect_failure(io::ErrorKind::NotFound, remove_dir_contents(&p.ours))?;
+        expect_failure(&[ENOENT], remove_dir_contents(&p.ours))?;
         Ok(())
     }
 
@@ -90,10 +118,10 @@ mod test {
     fn ensure_rm() -> Result<(), io::Error> {
         let p = prep()?;
 
-        expect_failure(io::ErrorKind::Other, ensure_empty_dir(&p.file))?;
+        expect_failure(&[ENOTDIR], ensure_empty_dir(&p.file))?;
 
         ensure_empty_dir(&p.ours)?;
-        expect_failure(io::ErrorKind::NotFound, File::open(&p.file))?;
+        expect_failure(&[ENOENT], File::open(&p.file))?;
         ensure_empty_dir(&p.ours)?;
 
         remove_dir_all(&p.ours)?;