diff --git a/tests/testsuite/alt_registry.rs b/tests/testsuite/alt_registry.rs
index 23c003ced..861cf9a82 100644
--- a/tests/testsuite/alt_registry.rs
+++ b/tests/testsuite/alt_registry.rs
@@ -1,4 +1,3 @@
-use support::ChannelChanger;
 use support::registry::{self, alt_api_path, Package};
 use support::{basic_manifest, execs, paths, project};
 use support::hamcrest::assert_that;
diff --git a/tests/testsuite/bench.rs b/tests/testsuite/bench.rs
index 603b1be3a..7f4a2d710 100644
--- a/tests/testsuite/bench.rs
+++ b/tests/testsuite/bench.rs
@@ -1,7 +1,7 @@
 use std::str;
 
 use cargo::util::process;
-use support::{is_nightly, ChannelChanger};
+use support::is_nightly;
 use support::paths::CargoPathExt;
 use support::{basic_manifest, basic_bin_manifest, basic_lib_manifest, execs, project};
 use support::hamcrest::{assert_that, existing_file};
diff --git a/tests/testsuite/build.rs b/tests/testsuite/build.rs
index 642c8acd5..5429f3af6 100644
--- a/tests/testsuite/build.rs
+++ b/tests/testsuite/build.rs
@@ -3,13 +3,12 @@ use std::fs::{self, File};
 use std::io::prelude::*;
 
 use cargo::util::paths::dylib_path_envvar;
-use cargo::util::{process, ProcessBuilder};
+use cargo::util::process;
 use support::{basic_manifest, basic_bin_manifest, basic_lib_manifest, is_nightly, rustc_host, sleep_ms};
 use support::paths::{root, CargoPathExt};
 use support::ProjectBuilder;
-use support::{execs, main_file, project};
+use support::{Execs, execs, main_file, project};
 use support::registry::Package;
-use support::ChannelChanger;
 use support::hamcrest::{assert_that, existing_dir, existing_file, is_not};
 
 #[test]
@@ -1553,15 +1552,15 @@ fn crate_authors_env_vars() {
 }
 
 // The tester may already have LD_LIBRARY_PATH=::/foo/bar which leads to a false positive error
-fn setenv_for_removing_empty_component(mut p: ProcessBuilder) -> ProcessBuilder {
+fn setenv_for_removing_empty_component(mut execs: Execs) -> Execs {
     let v = dylib_path_envvar();
     if let Ok(search_path) = env::var(v) {
         let new_search_path = env::join_paths(
             env::split_paths(&search_path).filter(|e| !e.as_os_str().is_empty()),
         ).expect("join_paths");
-        p.env(v, new_search_path); // build_command() will override LD_LIBRARY_PATH accordingly
+        execs.env(v, new_search_path); // build_command() will override LD_LIBRARY_PATH accordingly
     }
-    p
+    execs
 }
 
 // Regression test for #4277
diff --git a/tests/testsuite/build_plan.rs b/tests/testsuite/build_plan.rs
index d2eeae26c..488d36831 100644
--- a/tests/testsuite/build_plan.rs
+++ b/tests/testsuite/build_plan.rs
@@ -1,4 +1,3 @@
-use support::ChannelChanger;
 use support::{basic_manifest, basic_bin_manifest, execs, main_file, project};
 use support::hamcrest::{assert_that, existing_file, is_not};
 
diff --git a/tests/testsuite/cargo_features.rs b/tests/testsuite/cargo_features.rs
index 73bb32ed7..1d622f1e3 100644
--- a/tests/testsuite/cargo_features.rs
+++ b/tests/testsuite/cargo_features.rs
@@ -1,4 +1,3 @@
-use support::ChannelChanger;
 use support::{execs, project, publish};
 use support::hamcrest::assert_that;
 
diff --git a/tests/testsuite/doc.rs b/tests/testsuite/doc.rs
index 5004c81de..901045507 100644
--- a/tests/testsuite/doc.rs
+++ b/tests/testsuite/doc.rs
@@ -3,7 +3,7 @@ use std::str;
 use std::fs::{self, File};
 use std::io::Read;
 
-use support::{is_nightly, rustc_host, ChannelChanger};
+use support::{is_nightly, rustc_host};
 use support::{basic_manifest, basic_lib_manifest, execs, git, project, path2url};
 use support::paths::CargoPathExt;
 use support::registry::Package;
diff --git a/tests/testsuite/edition.rs b/tests/testsuite/edition.rs
index c3926091c..59adeaa78 100644
--- a/tests/testsuite/edition.rs
+++ b/tests/testsuite/edition.rs
@@ -1,5 +1,4 @@
 use support::{basic_lib_manifest, is_nightly, execs, project};
-use support::ChannelChanger;
 use support::hamcrest::assert_that;
 
 #[test]
diff --git a/tests/testsuite/features.rs b/tests/testsuite/features.rs
index 17524b96c..6bb9f1a95 100644
--- a/tests/testsuite/features.rs
+++ b/tests/testsuite/features.rs
@@ -3,7 +3,6 @@ use std::io::prelude::*;
 
 use support::paths::CargoPathExt;
 use support::{basic_manifest, execs, project};
-use support::ChannelChanger;
 use support::hamcrest::assert_that;
 use support::registry::Package;
 
diff --git a/tests/testsuite/fix.rs b/tests/testsuite/fix.rs
index 0ad9d5502..b03fb0c11 100644
--- a/tests/testsuite/fix.rs
+++ b/tests/testsuite/fix.rs
@@ -4,7 +4,7 @@ use git2;
 
 use support::git;
 use support::{basic_manifest, execs, project};
-use support::{is_nightly, ChannelChanger};
+use support::is_nightly;
 use support::hamcrest::assert_that;
 
 #[test]
diff --git a/tests/testsuite/generate_lockfile.rs b/tests/testsuite/generate_lockfile.rs
index f25cb2338..ce02ac453 100644
--- a/tests/testsuite/generate_lockfile.rs
+++ b/tests/testsuite/generate_lockfile.rs
@@ -3,7 +3,6 @@ use std::io::prelude::*;
 
 use support::registry::Package;
 use support::{basic_manifest, execs, paths, project, ProjectBuilder};
-use support::ChannelChanger;
 use support::hamcrest::{assert_that, existing_file, is_not};
 
 #[test]
diff --git a/tests/testsuite/git.rs b/tests/testsuite/git.rs
index d4614eddf..62cb6ffe7 100644
--- a/tests/testsuite/git.rs
+++ b/tests/testsuite/git.rs
@@ -11,7 +11,6 @@ use cargo::util::process;
 use support::sleep_ms;
 use support::paths::{self, CargoPathExt};
 use support::{basic_manifest, basic_lib_manifest, execs, git, main_file, project, path2url};
-use support::ChannelChanger;
 use support::hamcrest::{assert_that, existing_file};
 
 #[test]
diff --git a/tests/testsuite/metabuild.rs b/tests/testsuite/metabuild.rs
index 460068775..1dcfca856 100644
--- a/tests/testsuite/metabuild.rs
+++ b/tests/testsuite/metabuild.rs
@@ -3,7 +3,7 @@ use serde_json;
 use std::str;
 use support::{
     basic_lib_manifest, basic_manifest, execs, hamcrest::assert_that, project, registry::Package,
-    rustc_host, ChannelChanger, Project,
+    rustc_host, Project,
 };
 
 #[test]
diff --git a/tests/testsuite/metadata.rs b/tests/testsuite/metadata.rs
index 2ad48f7db..f2e3ea656 100644
--- a/tests/testsuite/metadata.rs
+++ b/tests/testsuite/metadata.rs
@@ -1,5 +1,5 @@
 use support::registry::Package;
-use support::{basic_bin_manifest, basic_lib_manifest, execs, main_file, project, ChannelChanger};
+use support::{basic_bin_manifest, basic_lib_manifest, execs, main_file, project};
 use support::hamcrest::assert_that;
 
 #[test]
diff --git a/tests/testsuite/out_dir.rs b/tests/testsuite/out_dir.rs
index 47a14be3b..6428b1c76 100644
--- a/tests/testsuite/out_dir.rs
+++ b/tests/testsuite/out_dir.rs
@@ -4,7 +4,7 @@ use std::env;
 
 use support::hamcrest::assert_that;
 
-use support::{process, sleep_ms, ChannelChanger};
+use support::{process, sleep_ms};
 use support::{basic_manifest, execs, project};
 
 #[test]
diff --git a/tests/testsuite/package.rs b/tests/testsuite/package.rs
index 7e431422a..ff3de7f17 100644
--- a/tests/testsuite/package.rs
+++ b/tests/testsuite/package.rs
@@ -4,7 +4,7 @@ use std::io::prelude::*;
 use std::path::{Path, PathBuf};
 
 use git2;
-use support::{cargo_process, sleep_ms, ChannelChanger};
+use support::{cargo_process, sleep_ms};
 use support::{basic_manifest, execs, git, is_nightly, paths, project, registry, path2url};
 use support::registry::Package;
 use flate2::read::GzDecoder;
diff --git a/tests/testsuite/profile_config.rs b/tests/testsuite/profile_config.rs
index 393693fcf..791cdc27b 100644
--- a/tests/testsuite/profile_config.rs
+++ b/tests/testsuite/profile_config.rs
@@ -1,5 +1,4 @@
 use support::{basic_lib_manifest, execs, paths, project};
-use support::ChannelChanger;
 use support::hamcrest::assert_that;
 
 #[test]
diff --git a/tests/testsuite/profile_overrides.rs b/tests/testsuite/profile_overrides.rs
index eb8ebb74c..7e678f17a 100644
--- a/tests/testsuite/profile_overrides.rs
+++ b/tests/testsuite/profile_overrides.rs
@@ -1,5 +1,4 @@
 use support::{basic_manifest, basic_lib_manifest, execs, project};
-use support::ChannelChanger;
 use support::hamcrest::assert_that;
 
 #[test]
diff --git a/tests/testsuite/publish.rs b/tests/testsuite/publish.rs
index bcc1d61c8..9bce776ff 100644
--- a/tests/testsuite/publish.rs
+++ b/tests/testsuite/publish.rs
@@ -2,7 +2,6 @@ use std::io::prelude::*;
 use std::fs::{self, File};
 use std::io::SeekFrom;
 
-use support::ChannelChanger;
 use support::git::repo;
 use support::paths;
 use support::{basic_manifest, execs, project, publish};
diff --git a/tests/testsuite/registry.rs b/tests/testsuite/registry.rs
index 64dad2e07..96adc786e 100644
--- a/tests/testsuite/registry.rs
+++ b/tests/testsuite/registry.rs
@@ -750,7 +750,6 @@ fn update_lockfile() {
 
 #[test]
 fn update_offline() {
-    use support::ChannelChanger;
     let p = project()
         .file(
             "Cargo.toml",
diff --git a/tests/testsuite/rename_deps.rs b/tests/testsuite/rename_deps.rs
index a725e71b0..2816b315c 100644
--- a/tests/testsuite/rename_deps.rs
+++ b/tests/testsuite/rename_deps.rs
@@ -1,4 +1,3 @@
-use support::ChannelChanger;
 use support::git;
 use support::paths;
 use support::registry::Package;
diff --git a/tests/testsuite/resolve.rs b/tests/testsuite/resolve.rs
index 2acaadab0..8e35ef921 100644
--- a/tests/testsuite/resolve.rs
+++ b/tests/testsuite/resolve.rs
@@ -8,7 +8,6 @@ use cargo::core::{Dependency, PackageId, Registry, Summary, enable_nightly_featu
 use cargo::util::{CargoResult, Config, ToUrl};
 use cargo::core::resolver::{self, Method};
 
-use support::ChannelChanger;
 use support::{execs, project};
 use support::registry::Package;
 
diff --git a/tests/testsuite/run.rs b/tests/testsuite/run.rs
index aaf50f96a..812d88136 100644
--- a/tests/testsuite/run.rs
+++ b/tests/testsuite/run.rs
@@ -1,5 +1,5 @@
 use cargo::util::paths::dylib_path_envvar;
-use support::{self, ChannelChanger};
+use support;
 use support::{basic_bin_manifest, basic_lib_manifest, execs, project, Project, path2url};
 use support::hamcrest::{assert_that, existing_file};
 
diff --git a/tests/testsuite/support/mod.rs b/tests/testsuite/support/mod.rs
index 47f8aaa38..7a07221b1 100644
--- a/tests/testsuite/support/mod.rs
+++ b/tests/testsuite/support/mod.rs
@@ -118,12 +118,12 @@ use std::fs;
 use std::io::prelude::*;
 use std::os;
 use std::path::{Path, PathBuf};
-use std::process::Output;
+use std::process::{Command, Output};
 use std::str;
 use std::time::Duration;
 use std::usize;
 
-use cargo::util::{ProcessBuilder, ProcessError, Rustc};
+use cargo::util::{CargoResult, ProcessBuilder, ProcessError, Rustc};
 use cargo;
 use serde_json::{self, Value};
 use url::Url;
@@ -384,10 +384,10 @@ impl Project {
     /// Arguments can be separated by spaces.
     /// Example:
     ///     assert_that(p.cargo("build --bin foo"), execs());
-    pub fn cargo(&self, cmd: &str) -> ProcessBuilder {
+    pub fn cargo(&self, cmd: &str) -> Execs {
         let mut p = self.process(&cargo_exe());
         split_and_add_args(&mut p, cmd);
-        p
+        execs().with_process_builder(p)
     }
 
     /// Returns the contents of `Cargo.lock`.
@@ -526,6 +526,8 @@ pub fn cargo_exe() -> PathBuf {
 #[must_use]
 #[derive(Clone)]
 pub struct Execs {
+    ran: bool,
+    process_builder: Option<ProcessBuilder>,
     expect_stdout: Option<String>,
     expect_stdin: Option<String>,
     expect_stderr: Option<String>,
@@ -543,6 +545,11 @@ pub struct Execs {
 }
 
 impl Execs {
+    pub fn with_process_builder(mut self, p: ProcessBuilder) -> Execs {
+        self.process_builder = Some(p);
+        self
+    }
+
     /// Verify that stdout is equal to the given lines.
     /// See `lines_match` for supported patterns.
     pub fn with_stdout<S: ToString>(&mut self, expected: S) -> &mut Self {
@@ -674,6 +681,59 @@ impl Execs {
         self
     }
 
+    pub fn arg<T: AsRef<OsStr>>(&mut self, arg: T) -> &mut Self {
+        if let Some(ref mut p) = self.process_builder {
+            p.arg(arg);
+        }
+        self
+    }
+
+    pub fn cwd<T: AsRef<OsStr>>(&mut self, path: T) -> &mut Self {
+        if let Some(ref mut p) = self.process_builder {
+            p.cwd(path);
+        }
+        self
+    }
+
+    pub fn env<T: AsRef<OsStr>>(&mut self, key: &str, val: T) -> &mut Self {
+        if let Some(ref mut p) = self.process_builder {
+            p.env(key, val);
+        }
+        self
+    }
+
+    pub fn env_remove(&mut self, key: &str) -> &mut Self {
+        if let Some(ref mut p) = self.process_builder {
+            p.env_remove(key);
+        }
+        self
+    }
+
+    pub fn exec_with_output(&self) -> CargoResult<Output> {
+        // TODO avoid unwrap
+        let p = (&self.process_builder).clone().unwrap();
+        p.exec_with_output()
+    }
+
+    pub fn build_command(&self) -> Command {
+        // TODO avoid unwrap
+        let p = (&self.process_builder).clone().unwrap();
+        p.build_command()
+    }
+
+    pub fn masquerade_as_nightly_cargo(&mut self) -> &mut Self {
+        if let Some(ref mut p) = self.process_builder {
+            p.masquerade_as_nightly_cargo();
+        }
+        self
+    }
+
+    #[allow(dead_code)]
+    pub fn run(&mut self) {
+        self.ran = true;
+        let p = (&self.process_builder).clone().unwrap();
+        ham::assert_that(p, self)
+    }
 
     fn match_process(&self, process: &ProcessBuilder) -> ham::MatchResult {
         println!("running {}", process);
@@ -1052,6 +1112,15 @@ impl Execs {
     }
 }
 
+impl Drop for Execs {
+    fn drop(&mut self) {
+        if !self.ran {
+            // TODO: Re-enable when everything goes through Execs#run
+            // panic!("forgot to run this command");
+        }
+    }
+}
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 enum MatchKind {
     Exact,
@@ -1187,6 +1256,40 @@ impl fmt::Debug for Execs {
     }
 }
 
+// TODO: Remove this temporary matcher while transitioning off of assert_that
+impl ham::Matcher<Execs> for Execs {
+    fn matches(&self, mut execs: Execs) -> ham::MatchResult {
+        self.matches(&mut execs)
+    }
+}
+
+// TODO: Remove this temporary matcher while transitioning off of assert_that
+impl<'a> ham::Matcher<&'a mut Execs> for Execs {
+    fn matches(&self, execs: &'a mut Execs) -> ham::MatchResult {
+        // TODO: avoid unwrap
+        let mut p = (&execs.process_builder).clone().unwrap();
+        self.matches(&mut p)
+    }
+}
+
+// TODO: Remove this temporary matcher while transitioning off of assert_that
+impl<'t> ham::Matcher<Execs> for &'t mut Execs {
+    fn matches(&self, execs: Execs) -> ham::MatchResult {
+        // TODO: avoid unwrap
+        let mut p = (&execs.process_builder).clone().unwrap();
+        self.matches(&mut p)
+    }
+}
+
+// TODO: Remove this temporary matcher while transitioning off of assert_that
+impl<'a, 't> ham::Matcher<&'a mut Execs> for &'t mut Execs {
+    fn matches(&self, execs: &'a mut Execs) -> ham::MatchResult {
+        // TODO: avoid unwrap
+        let mut p = (&execs.process_builder).clone().unwrap();
+        self.matches(&mut p)
+    }
+}
+
 impl ham::Matcher<ProcessBuilder> for Execs {
     fn matches(&self, process: ProcessBuilder) -> ham::MatchResult {
         self.match_process(&process)
@@ -1225,6 +1328,8 @@ impl<'t> ham::Matcher<Output> for &'t mut Execs {
 
 pub fn execs() -> Execs {
     Execs {
+        ran: false,
+        process_builder: None,
         expect_stdout: None,
         expect_stderr: None,
         expect_stdin: None,