diff --git a/Cargo.lock b/Cargo.lock
index efd7bd7..18325fb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -8,38 +8,11 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f5cde24d1b2e2216a726368b2363a273739c91f4e3eb4e0dd12d672d396ad989"
 
-[[package]]
-name = "byteorder"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c40977b0ee6b9885c9013cd41d9feffdd22deb3bb4dc3a71d901cc7a77de18c8"
-
-[[package]]
-name = "bytes"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86503b85bb937cbdf6e63f0e9d0b7ec3bbe1b40041865bdab199d33ddb03a18a"
-dependencies = [
- "byteorder",
-]
-
-[[package]]
-name = "cfg-if"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de1e760d7b6535af4241fca8bd8adf68e2e7edacc6b29f5d399050c5e48cf88c"
-
-[[package]]
-name = "cfg-if"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
-
 [[package]]
 name = "fuchsia-zircon"
-version = "0.3.2"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd510087c325af53ba24f3be8f1c081b0982319adcb8b03cad764512923ccc19"
+checksum = "3b5365afd01fdf916e775a224e844f80b3b9710d0f4f00903e219e859474d7ae"
 dependencies = [
  "bitflags",
  "fuchsia-zircon-sys",
@@ -47,176 +20,23 @@ dependencies = [
 
 [[package]]
 name = "fuchsia-zircon-sys"
-version = "0.3.2"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08b3a6f13ad6b96572b53ce7af74543132f1a7055ccceb6d073dd36c54481859"
-
-[[package]]
-name = "futures"
-version = "0.1.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0bab5b5e94f5c31fc764ba5dd9ad16568aae5d4825538c01d6bca680c9bf94a7"
-
-[[package]]
-name = "iovec"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b6e8b9c2247fcf6c6a1151f1156932be5606c9fd6f55a2d7f9fc1cb29386b2f7"
-dependencies = [
- "libc 0.2.54",
- "winapi 0.2.4",
-]
+checksum = "069def9a0e5feb7e9120635f6ebad24d853a6affbb077fec84d0888316cf9ae6"
 
 [[package]]
 name = "jobserver"
 version = "0.1.28"
 dependencies = [
- "futures",
- "libc 0.2.54",
- "num_cpus",
+ "libc",
  "tempfile",
- "tokio-core",
- "tokio-process",
-]
-
-[[package]]
-name = "kernel32-sys"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad1ca084b49bfd975182288e1a5f1d27ea34ff2d6ae084ae5e66e1652427eada"
-dependencies = [
- "winapi 0.2.4",
- "winapi-build",
 ]
 
-[[package]]
-name = "lazycell"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ec38a5c22f1ef3e30d2642aa875620d60edeef36cef43c4739d86215ce816331"
-
-[[package]]
-name = "lazycell"
-version = "0.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a6f08839bc70ef4a3fe1d566d5350f519c5912ea86be0df1740a7d247c7fc0ef"
-
 [[package]]
 name = "libc"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "367f169cc2ae9afbe5c7309b3d5c34dced82e9da121104d2b826cf2aee3502ae"
-
-[[package]]
-name = "libc"
-version = "0.2.54"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c6785aa7dd976f5fbf3b71cfd9cd49d7f783c1ff565a858d71031c6c313aa5c6"
-
-[[package]]
-name = "log"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b2b224ebf7a4745d17092755d196ea731205e68d6d8e9987015131434725594"
-dependencies = [
- "libc 0.1.0",
-]
-
-[[package]]
-name = "log"
-version = "0.4.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
-dependencies = [
- "cfg-if 1.0.0",
-]
-
-[[package]]
-name = "mio"
-version = "0.6.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d771e3ef92d58a8da8df7d6976bfca9371ed1de6619d9d5a5ce5b1f29b85bfe"
-dependencies = [
- "fuchsia-zircon",
- "fuchsia-zircon-sys",
- "iovec",
- "kernel32-sys",
- "lazycell 0.6.0",
- "libc 0.2.54",
- "log 0.4.14",
- "miow 0.2.2",
- "net2",
- "slab 0.4.0",
- "winapi 0.2.4",
-]
-
-[[package]]
-name = "mio-named-pipes"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ea8f1e005b1f0cddae23d34af820144bf3785623e3dd3bee23dc08fd913830e8"
-dependencies = [
- "kernel32-sys",
- "lazycell 0.5.0",
- "log 0.3.0",
- "mio",
- "miow 0.1.4",
- "winapi 0.2.4",
-]
-
-[[package]]
-name = "mio-uds"
-version = "0.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b6bd83b05675b13929d3c3add6c8cabf0067a63e8bb56bf231b8203946e0aa7"
-dependencies = [
- "libc 0.2.54",
- "mio",
-]
-
-[[package]]
-name = "miow"
-version = "0.1.4"
+version = "0.2.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c6b54090eaa23880441a80c4adec5fd6b4af1152a49c5e78f96a82469abc6942"
-dependencies = [
- "kernel32-sys",
- "net2",
- "winapi 0.2.4",
- "ws2_32-sys",
-]
-
-[[package]]
-name = "miow"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ebd808424166322d4a38da87083bfddd3ac4c131334ed55856112eb06d46944d"
-dependencies = [
- "kernel32-sys",
- "net2",
- "winapi 0.2.4",
- "ws2_32-sys",
-]
-
-[[package]]
-name = "net2"
-version = "0.2.36"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7cf75f38f16cb05ea017784dc6dbfd354f76c223dba37701734c4f5a9337d02"
-dependencies = [
- "cfg-if 0.1.0",
- "libc 0.2.54",
- "winapi 0.3.0",
-]
-
-[[package]]
-name = "num_cpus"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a859041cbf7a70ea1ece4b87d1a2c6ef364dcb68749c88db1f97304b9ec09d5f"
-dependencies = [
- "libc 0.2.54",
-]
+checksum = "aab692d7759f5cd8c859e169db98ae5b52c924add2af5fbbca11d12fefb567c1"
 
 [[package]]
 name = "rand"
@@ -225,7 +45,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d5f78082e6a6d042862611e9640cf20776185fee506cf6cf67e93c6225cee31"
 dependencies = [
  "fuchsia-zircon",
- "libc 0.2.54",
+ "libc",
 ]
 
 [[package]]
@@ -240,125 +60,22 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dfc5b3ce5d5ea144bb04ebd093a9e14e9765bcfec866aecda9b6dec43b3d1e24"
 dependencies = [
- "winapi 0.3.0",
+ "winapi",
 ]
 
-[[package]]
-name = "scoped-tls"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f417c22df063e9450888a7561788e9bd46d3bb3c1466435b4eccb903807f147d"
-
-[[package]]
-name = "slab"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17b4fcaed89ab08ef143da37bc52adbcc04d4a69014f4c1208d6b51f0c47bc23"
-
-[[package]]
-name = "slab"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fdeff4cd9ecff59ec7e3744cbca73dfe5ac35c2aedb2cfba8a1c715a18912e9d"
-
 [[package]]
 name = "tempfile"
 version = "3.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47776f63b85777d984a50ce49d6b9e58826b6a3766a449fc95bc66cd5663c15b"
 dependencies = [
- "libc 0.2.54",
+ "libc",
  "rand",
  "redox_syscall",
  "remove_dir_all",
- "winapi 0.3.0",
-]
-
-[[package]]
-name = "tokio-core"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "659cbae6c954dee37352853816c6a52180e47feb70be73bbfeec6d58c4da4a71"
-dependencies = [
- "futures",
- "log 0.3.0",
- "mio",
- "scoped-tls",
- "slab 0.3.0",
-]
-
-[[package]]
-name = "tokio-executor"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "46108c2aca0eb4b9a883bf37a28d122ca70f5318446f59f729cd1ff78a0bb5fb"
-dependencies = [
- "futures",
-]
-
-[[package]]
-name = "tokio-io"
-version = "0.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6af9eb326f64b2d6b68438e1953341e00ab3cf54de7e35d92bfc73af8555313a"
-dependencies = [
- "bytes",
- "futures",
- "log 0.4.14",
+ "winapi",
 ]
 
-[[package]]
-name = "tokio-process"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "81de38febefe683adab7070c0f705afd6247582d0b1780d9eb745c77a0d4e88b"
-dependencies = [
- "futures",
- "libc 0.2.54",
- "mio",
- "mio-named-pipes",
- "tokio-io",
- "tokio-reactor",
- "tokio-signal",
- "winapi 0.3.0",
-]
-
-[[package]]
-name = "tokio-reactor"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f21d00eb356854d502b81776cec931d12771e4ed6d198478d23ffd38c19279af"
-dependencies = [
- "futures",
- "log 0.4.14",
- "mio",
- "slab 0.4.0",
- "tokio-executor",
- "tokio-io",
-]
-
-[[package]]
-name = "tokio-signal"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a6a5bf935a0151cc8899aa806ce6a425bdaec79ed4034de1a1e6bfa247e2def"
-dependencies = [
- "futures",
- "libc 0.2.54",
- "mio",
- "mio-uds",
- "tokio-executor",
- "tokio-io",
- "tokio-reactor",
- "winapi 0.3.0",
-]
-
-[[package]]
-name = "winapi"
-version = "0.2.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5350e40d908c7e8b9e5c9edb541ca47cc617c6229d3575a46da6f550f36c96fd"
-
 [[package]]
 name = "winapi"
 version = "0.3.0"
@@ -369,12 +86,6 @@ dependencies = [
  "winapi-x86_64-pc-windows-gnu",
 ]
 
-[[package]]
-name = "winapi-build"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
-
 [[package]]
 name = "winapi-i686-pc-windows-gnu"
 version = "0.3.0"
@@ -386,13 +97,3 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ca29cb03c8ceaf20f8224a18a530938305e9872b1478ea24ff44b4f503a1d1d"
-
-[[package]]
-name = "ws2_32-sys"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee5f6c385b5f769b6e6104dce4d46dbb582d4bca1e7db77157766381636ee9d8"
-dependencies = [
- "winapi 0.2.4",
- "winapi-build",
-]
diff --git a/Cargo.toml b/Cargo.toml
index 9e94b53..b4cdcda 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,11 +16,7 @@ rust-version = "1.63"
 libc = "0.2.50"
 
 [dev-dependencies]
-futures = "0.1"
-num_cpus = "1.0"
 tempfile = "3"
-tokio-core = "0.1"
-tokio-process = "0.2"
 
 [[test]]
 name = "client"
diff --git a/tests/client.rs b/tests/client.rs
index 2516b8c..f10a10c 100644
--- a/tests/client.rs
+++ b/tests/client.rs
@@ -7,11 +7,7 @@ use std::sync::mpsc;
 use std::sync::Arc;
 use std::thread;
 
-use futures::future::{self, Future};
-use futures::stream::{self, Stream};
 use jobserver::Client;
-use tokio_core::reactor::Core;
-use tokio_process::CommandExt;
 
 macro_rules! t {
     ($e:expr) => {
@@ -24,9 +20,9 @@ macro_rules! t {
 
 struct Test {
     name: &'static str,
-    f: &'static dyn Fn(),
+    f: &'static (dyn Fn() + Send + Sync),
     make_args: &'static [&'static str],
-    rule: &'static dyn Fn(&str) -> String,
+    rule: &'static (dyn Fn(&str) -> String + Send + Sync),
 }
 
 const TESTS: &[Test] = &[
@@ -118,9 +114,7 @@ fn main() {
     let me = me.to_str().unwrap();
     let filter = env::args().nth(1);
 
-    let mut core = t!(Core::new());
-
-    let futures = TESTS
+    let join_handles = TESTS
         .iter()
         .filter(|test| match filter {
             Some(ref s) => test.name.contains(s),
@@ -138,33 +132,33 @@ all:
                 (test.rule)(me)
             );
             t!(t!(File::create(td.path().join("Makefile"))).write_all(makefile.as_bytes()));
-            let prog = env::var("MAKE").unwrap_or_else(|_| "make".to_string());
-            let mut cmd = Command::new(prog);
-            cmd.args(test.make_args);
-            cmd.current_dir(td.path());
-            future::lazy(move || {
-                cmd.output_async().map(move |e| {
-                    drop(td);
-                    (test, e)
-                })
+            thread::spawn(move || {
+                let prog = env::var("MAKE").unwrap_or_else(|_| "make".to_string());
+                let mut cmd = Command::new(prog);
+                cmd.args(test.make_args);
+                cmd.current_dir(td.path());
+
+                (test, cmd.output().unwrap())
             })
         })
         .collect::<Vec<_>>();
 
-    println!("\nrunning {} tests\n", futures.len());
+    println!("\nrunning {} tests\n", join_handles.len());
 
-    let stream = stream::iter(futures.into_iter().map(Ok)).buffer_unordered(num_cpus::get());
+    let failures = join_handles
+        .into_iter()
+        .filter_map(|join_handle| {
+            let (test, output) = join_handle.join().unwrap();
 
-    let mut failures = Vec::new();
-    t!(core.run(stream.for_each(|(test, output)| {
-        if output.status.success() {
-            println!("test {} ... ok", test.name);
-        } else {
-            println!("test {} ... FAIL", test.name);
-            failures.push((test, output));
-        }
-        Ok(())
-    })));
+            if output.status.success() {
+                println!("test {} ... ok", test.name);
+                None
+            } else {
+                println!("test {} ... FAIL", test.name);
+                Some((test, output))
+            }
+        })
+        .collect::<Vec<_>>();
 
     if failures.is_empty() {
         println!("\ntest result: ok\n");