diff --git a/tests/cache_check.rs b/tests/cache_check.rs
index 45c1995..b3e9c9a 100644
--- a/tests/cache_check.rs
+++ b/tests/cache_check.rs
@@ -41,7 +41,7 @@ impl<'a> Program<'a> for CacheCheck {
         "cache_check"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/cache_dump.rs b/tests/cache_dump.rs
index 63c5933..7cea5b0 100644
--- a/tests/cache_dump.rs
+++ b/tests/cache_dump.rs
@@ -41,7 +41,7 @@ impl<'a> Program<'a> for CacheDump {
         "cache_dump"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/cache_repair.rs b/tests/cache_repair.rs
index 95c08cc..524b376 100644
--- a/tests/cache_repair.rs
+++ b/tests/cache_repair.rs
@@ -37,7 +37,7 @@ impl<'a> Program<'a> for CacheRepair {
         "cache_repair"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/cache_restore.rs b/tests/cache_restore.rs
index 4eaa51c..aebc6d1 100644
--- a/tests/cache_restore.rs
+++ b/tests/cache_restore.rs
@@ -39,7 +39,7 @@ impl<'a> Program<'a> for CacheRestore {
         "thin_restore"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/common/process.rs b/tests/common/process.rs
index 2d74d1c..0338c60 100644
--- a/tests/common/process.rs
+++ b/tests/common/process.rs
@@ -1,4 +1,7 @@
 use anyhow::Result;
+use std::ffi::OsString;
+use std::fmt;
+use std::process;
 
 //------------------------------------------
 
@@ -13,11 +16,65 @@ macro_rules! args {
     };
 }
 
+/// Holds a set of arguments for a shell command
+#[derive(Debug)]
+pub struct Command {
+    program: OsString,
+    args: Vec<OsString>,
+}
+
+#[macro_export]
+macro_rules! cmd {
+    ( $program:expr $(, $arg:expr )* $(,)? ) => {
+        {
+          //  use std::ffi::OsString;
+            let args: &[OsString] = &[$( Into::<OsString>::into($arg) ),*];
+            Command::new($program, args)
+        }
+    };
+}
+
+impl Command {
+    pub fn new(program: OsString, args: Vec<OsString>) -> Self {
+        Command { program, args }
+    }
+
+    fn to_expr(&self) -> duct::Expression {
+        duct::cmd(&self.program, &self.args)
+    }
+}
+
+impl fmt::Display for Command {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.program.clone().into_string().unwrap())?;
+        for a in &self.args {
+            write!(f, " {}", a.clone().into_string().unwrap())?;
+        }
+        Ok(())
+    }
+}
+
+fn log_output(output: &process::Output) {
+    use std::str::from_utf8;
+
+    if output.stdout.len() > 0 {
+        eprintln!("stdout: {:?}", from_utf8(&output.stdout));
+    }
+    if output.stderr.len() > 0 {
+        eprintln!("stderr: {:?}", from_utf8(&output.stderr));
+    }
+}
+
 // Returns stdout. The command must return zero.
-pub fn run_ok(command: duct::Expression) -> Result<String> {
-    let command = command.stdout_capture().stderr_capture();
+pub fn run_ok(command: Command) -> Result<String> {
+    eprintln!("run_ok: {}", command);
+
+    let command = command.to_expr().stdout_capture().stderr_capture();
     let output = command.run()?;
+
+    log_output(&output);
     assert!(output.status.success());
+
     let stdout = std::str::from_utf8(&output.stdout[..])
         .unwrap()
         .trim_end_matches(|c| c == '\n' || c == '\r')
@@ -27,26 +84,32 @@ pub fn run_ok(command: duct::Expression) -> Result<String> {
 }
 
 // Returns the entire output. The command must return zero.
-pub fn run_ok_raw(command: duct::Expression) -> Result<std::process::Output> {
-    let command = command.stdout_capture().stderr_capture();
+pub fn run_ok_raw(command: Command) -> Result<std::process::Output> {
+    eprintln!("run_ok_raw: {}", command);
+    let command = command.to_expr().stdout_capture().stderr_capture();
     let output = command.run()?;
+    log_output(&output);
     assert!(output.status.success());
     Ok(output)
 }
 
 // Returns stderr, a non zero status must be returned
-pub fn run_fail(command: duct::Expression) -> Result<String> {
-    let command = command.stdout_capture().stderr_capture();
+pub fn run_fail(command: Command) -> Result<String> {
+    eprintln!("run_fail: {}", command);
+    let command = command.to_expr().stdout_capture().stderr_capture();
     let output = command.unchecked().run()?;
+    log_output(&output);
     assert!(!output.status.success());
     let stderr = std::str::from_utf8(&output.stderr[..]).unwrap().to_string();
     Ok(stderr)
 }
 
 // Returns the entire output, a non zero status must be returned
-pub fn run_fail_raw(command: duct::Expression) -> Result<std::process::Output> {
-    let command = command.stdout_capture().stderr_capture();
+pub fn run_fail_raw(command: Command) -> Result<std::process::Output> {
+    eprintln!("run_fail_raw: {}", command);
+    let command = command.to_expr().stdout_capture().stderr_capture();
     let output = command.unchecked().run()?;
+    log_output(&output);
     assert!(!output.status.success());
     Ok(output)
 }
diff --git a/tests/common/program.rs b/tests/common/program.rs
index fd15639..f006202 100644
--- a/tests/common/program.rs
+++ b/tests/common/program.rs
@@ -1,6 +1,7 @@
 use anyhow::Result;
 use std::path::PathBuf;
 
+pub use crate::common::process::*;
 use crate::common::test_dir::TestDir;
 
 //------------------------------------------
@@ -12,7 +13,7 @@ pub enum ArgType {
 
 pub trait Program<'a> {
     fn name() -> &'a str;
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>;
diff --git a/tests/common/target.rs b/tests/common/target.rs
index 965f94e..6a91930 100644
--- a/tests/common/target.rs
+++ b/tests/common/target.rs
@@ -1,20 +1,28 @@
 use std::ffi::OsString;
 use std::path::PathBuf;
 
+use crate::common::process::*;
+
 //------------------------------------------
 
-pub fn cpp_cmd<S, I>(cmd: S, args: I) -> duct::Expression
+pub fn cpp_cmd<S, I>(cmd: S, args: I) -> Command
 where
     S: Into<OsString>,
     I: IntoIterator,
     I::Item: Into<OsString>,
 {
-    let mut bin = PathBuf::from("./bin");
+    let mut bin = PathBuf::from("bin");
     bin.push(Into::<OsString>::into(cmd));
-    duct::cmd(bin.as_path(), args)
+
+    let mut args_ = Vec::new();
+    for a in args {
+        args_.push(Into::<OsString>::into(a));
+    }
+
+    Command::new(Into::<OsString>::into(bin.as_path()), args_)
 }
 
-pub fn rust_cmd<S, I>(cmd: S, args: I) -> duct::Expression
+pub fn rust_cmd<S, I>(cmd: S, args: I) -> Command
 where
     S: Into<OsString>,
     I: IntoIterator,
@@ -27,10 +35,10 @@ where
         all_args.push(Into::<OsString>::into(a));
     }
 
-    duct::cmd(RUST_PATH, &all_args)
+    Command::new(Into::<OsString>::into(RUST_PATH), all_args)
 }
 
-pub fn thin_check_cmd<I>(args: I) -> duct::Expression
+pub fn thin_check_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -38,7 +46,7 @@ where
     rust_cmd("thin_check", args)
 }
 
-pub fn thin_rmap_cmd<I>(args: I) -> duct::Expression
+pub fn thin_rmap_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -46,7 +54,7 @@ where
     cpp_cmd("thin_rmap", args)
 }
 
-pub fn thin_generate_metadata_cmd<I>(args: I) -> duct::Expression
+pub fn thin_generate_metadata_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -54,7 +62,7 @@ where
     cpp_cmd("thin_generate_metadata", args)
 }
 
-pub fn thin_generate_mappings_cmd<I>(args: I) -> duct::Expression
+pub fn thin_generate_mappings_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -62,7 +70,7 @@ where
     cpp_cmd("thin_generate_mappings", args)
 }
 
-pub fn thin_generate_damage_cmd<I>(args: I) -> duct::Expression
+pub fn thin_generate_damage_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -70,7 +78,16 @@ where
     cpp_cmd("thin_generate_damage", args)
 }
 
-pub fn thin_restore_cmd<I>(args: I) -> duct::Expression
+pub fn thin_restore_cmd<I>(args: I) -> Command
+where
+    I: IntoIterator,
+    I::Item: Into<OsString>,
+{
+    // rust_cmd("thin_restore", args)
+    cpp_cmd("thin_restore", args)
+}
+
+pub fn thin_repair_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -78,15 +95,7 @@ where
     rust_cmd("thin_restore", args)
 }
 
-pub fn thin_repair_cmd<I>(args: I) -> duct::Expression
-where
-    I: IntoIterator,
-    I::Item: Into<OsString>,
-{
-    rust_cmd("thin_restore", args)
-}
-
-pub fn thin_dump_cmd<I>(args: I) -> duct::Expression
+pub fn thin_dump_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -94,7 +103,7 @@ where
     rust_cmd("thin_dump", args)
 }
 
-pub fn thin_delta_cmd<I>(args: I) -> duct::Expression
+pub fn thin_delta_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -102,7 +111,7 @@ where
     cpp_cmd("thin_delta", args)
 }
 
-pub fn thin_metadata_pack_cmd<I>(args: I) -> duct::Expression
+pub fn thin_metadata_pack_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -110,7 +119,7 @@ where
     rust_cmd("thin_metadata_pack", args)
 }
 
-pub fn thin_metadata_unpack_cmd<I>(args: I) -> duct::Expression
+pub fn thin_metadata_unpack_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -118,7 +127,7 @@ where
     rust_cmd("thin_metadata_unpack", args)
 }
 
-pub fn cache_check_cmd<I>(args: I) -> duct::Expression
+pub fn cache_check_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -126,7 +135,7 @@ where
     rust_cmd("cache_check", args)
 }
 
-pub fn cache_dump_cmd<I>(args: I) -> duct::Expression
+pub fn cache_dump_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -134,7 +143,7 @@ where
     rust_cmd("cache_dump", args)
 }
 
-pub fn cache_restore_cmd<I>(args: I) -> duct::Expression
+pub fn cache_restore_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
@@ -142,7 +151,7 @@ where
     rust_cmd("cache_restore", args)
 }
 
-pub fn cache_repair_cmd<I>(args: I) -> duct::Expression
+pub fn cache_repair_cmd<I>(args: I) -> Command
 where
     I: IntoIterator,
     I::Item: Into<OsString>,
diff --git a/tests/common/test_dir.rs b/tests/common/test_dir.rs
index a71525a..3a0f837 100644
--- a/tests/common/test_dir.rs
+++ b/tests/common/test_dir.rs
@@ -36,6 +36,10 @@ impl TestDir {
         })
     }
 
+    pub fn dont_clean_up(&mut self) {
+        self.clean_up = false;
+    }
+
     pub fn mk_path(&mut self, file: &str) -> PathBuf {
         let mut p = PathBuf::new();
         p.push(&self.dir);
@@ -54,6 +58,8 @@ impl Drop for TestDir {
                 let _ignore = fs::remove_file(f);
             }
             fs::remove_dir(&self.dir).expect("couldn't remove test directory");
+        } else {
+            eprintln!("leaving test directory: {:?}", self.dir);
         }
     }
 }
diff --git a/tests/thin_check.rs b/tests/thin_check.rs
index d89e497..52688cf 100644
--- a/tests/thin_check.rs
+++ b/tests/thin_check.rs
@@ -45,7 +45,7 @@ impl<'a> Program<'a> for ThinCheck {
         "thin_check"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
@@ -315,17 +315,26 @@ fn fatal_errors_cant_be_ignored() -> Result<()> {
 #[test]
 fn auto_repair() -> Result<()> {
     let mut td = TestDir::new()?;
+    td.dont_clean_up();
     let md = prep_metadata(&mut td)?;
 
+    eprintln!("here 0");
+
     // auto-repair should have no effect on good metadata.
     ensure_untouched(&md, || {
-        run_ok(thin_check_cmd(args!["--auto-repair", &md]))?;
+        // run_ok(thin_check_cmd(args!["--auto-repair", &md]))?;
+        run_ok(thin_check_cmd(args![&md]))?;
         Ok(())
     })?;
+    eprintln!("here 0.5");
 
     generate_metadata_leaks(&md, 16, 0, 1)?;
+    eprintln!("here 1");
     run_fail(thin_check_cmd(args![&md]))?;
+    eprintln!("here 2");
     run_ok(thin_check_cmd(args!["--auto-repair", &md]))?;
+    eprintln!("here 3");
+
     run_ok(thin_check_cmd(args![&md]))?;
     Ok(())
 }
diff --git a/tests/thin_delta.rs b/tests/thin_delta.rs
index 4b9cba0..b2d57a7 100644
--- a/tests/thin_delta.rs
+++ b/tests/thin_delta.rs
@@ -29,7 +29,7 @@ impl<'a> Program<'a> for ThinDelta {
         "thin_delta"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/thin_dump.rs b/tests/thin_dump.rs
index 1ce6926..990a3bb 100644
--- a/tests/thin_dump.rs
+++ b/tests/thin_dump.rs
@@ -35,7 +35,7 @@ impl<'a> Program<'a> for ThinDump {
         "thin_dump"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/thin_metadata_pack.rs b/tests/thin_metadata_pack.rs
index 23e573f..86c7856 100644
--- a/tests/thin_metadata_pack.rs
+++ b/tests/thin_metadata_pack.rs
@@ -38,7 +38,7 @@ impl<'a> Program<'a> for ThinMetadataPack {
         "thin_metadata_pack"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/thin_metadata_unpack.rs b/tests/thin_metadata_unpack.rs
index bdbadb1..2e5d6c3 100644
--- a/tests/thin_metadata_unpack.rs
+++ b/tests/thin_metadata_unpack.rs
@@ -40,7 +40,7 @@ impl<'a> Program<'a> for ThinMetadataUnpack {
         "thin_metadata_pack"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/thin_repair.rs b/tests/thin_repair.rs
index e99a0ea..f8264e2 100644
--- a/tests/thin_repair.rs
+++ b/tests/thin_repair.rs
@@ -33,7 +33,7 @@ impl<'a> Program<'a> for ThinRepair {
         "thin_repair"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/thin_restore.rs b/tests/thin_restore.rs
index 6eae528..4d88352 100644
--- a/tests/thin_restore.rs
+++ b/tests/thin_restore.rs
@@ -34,7 +34,7 @@ impl<'a> Program<'a> for ThinRestore {
         "thin_restore"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,
diff --git a/tests/thin_rmap.rs b/tests/thin_rmap.rs
index 699e85f..f30bf32 100644
--- a/tests/thin_rmap.rs
+++ b/tests/thin_rmap.rs
@@ -29,7 +29,7 @@ impl<'a> Program<'a> for ThinRmap {
         "thin_rmap"
     }
 
-    fn cmd<I>(args: I) -> duct::Expression
+    fn cmd<I>(args: I) -> Command
     where
         I: IntoIterator,
         I::Item: Into<std::ffi::OsString>,