diff --git a/crate2nix/Cargo.nix b/crate2nix/Cargo.nix
index c848dcdd..dd07ebd4 100644
--- a/crate2nix/Cargo.nix
+++ b/crate2nix/Cargo.nix
@@ -3284,7 +3284,10 @@ rec {
           let
             drv = testCrate.override (_: {
               buildTests = true;
-            });
+            } // (lib.optionalAttrs (testCrate ? testedCrate) {
+              # if nixpkgs is recent enough to support testedCrate, provide it
+              testedCrate = testCrate;
+            }));
             # If the user hasn't set any pre/post commands, we don't want to
             # insert empty lines. This means that any existing users of crate2nix
             # don't get a spurious rebuild unless they set these explicitly.
diff --git a/crate2nix/templates/nix/crate2nix/default.nix b/crate2nix/templates/nix/crate2nix/default.nix
index 5b810733..c1b7f328 100644
--- a/crate2nix/templates/nix/crate2nix/default.nix
+++ b/crate2nix/templates/nix/crate2nix/default.nix
@@ -155,7 +155,10 @@ rec {
           let
             drv = testCrate.override (_: {
               buildTests = true;
-            });
+            } // (lib.optionalAttrs (testCrate ? testedCrate) {
+              # if nixpkgs is recent enough to support testedCrate, provide it
+              testedCrate = testCrate;
+            }));
             # If the user hasn't set any pre/post commands, we don't want to
             # insert empty lines. This means that any existing users of crate2nix
             # don't get a spurious rebuild unless they set these explicitly.
diff --git a/sample_projects/bin_with_git_submodule_dep/Cargo.nix b/sample_projects/bin_with_git_submodule_dep/Cargo.nix
index fad04a12..931ed1e8 100644
--- a/sample_projects/bin_with_git_submodule_dep/Cargo.nix
+++ b/sample_projects/bin_with_git_submodule_dep/Cargo.nix
@@ -1502,7 +1502,10 @@ rec {
           let
             drv = testCrate.override (_: {
               buildTests = true;
-            });
+            } // (lib.optionalAttrs (testCrate ? testedCrate) {
+              # if nixpkgs is recent enough to support testedCrate, provide it
+              testedCrate = testCrate;
+            }));
             # If the user hasn't set any pre/post commands, we don't want to
             # insert empty lines. This means that any existing users of crate2nix
             # don't get a spurious rebuild unless they set these explicitly.
diff --git a/sample_projects/codegen/Cargo.nix b/sample_projects/codegen/Cargo.nix
index b25e3f07..69f037f4 100644
--- a/sample_projects/codegen/Cargo.nix
+++ b/sample_projects/codegen/Cargo.nix
@@ -677,7 +677,10 @@ rec {
           let
             drv = testCrate.override (_: {
               buildTests = true;
-            });
+            } // (lib.optionalAttrs (testCrate ? testedCrate) {
+              # if nixpkgs is recent enough to support testedCrate, provide it
+              testedCrate = testCrate;
+            }));
             # If the user hasn't set any pre/post commands, we don't want to
             # insert empty lines. This means that any existing users of crate2nix
             # don't get a spurious rebuild unless they set these explicitly.
diff --git a/sample_projects/future_util_multi_version/result b/sample_projects/future_util_multi_version/result
deleted file mode 120000
index 461ee4d9..00000000
--- a/sample_projects/future_util_multi_version/result
+++ /dev/null
@@ -1 +0,0 @@
-/nix/store/99x50q7l9a3zih8ak94ka8j34rjl0fag-rust_future_util_multi_version-0.1.0
\ No newline at end of file
diff --git a/sample_projects/integration_test_with_envvar/Cargo.lock b/sample_projects/integration_test_with_envvar/Cargo.lock
new file mode 100644
index 00000000..7d751d1a
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "integration_test_with_envvar"
+version = "0.1.0"
diff --git a/sample_projects/integration_test_with_envvar/Cargo.toml b/sample_projects/integration_test_with_envvar/Cargo.toml
new file mode 100644
index 00000000..1500c2b1
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/Cargo.toml
@@ -0,0 +1,5 @@
+[package]
+name = "integration_test_with_envvar"
+version = "0.1.0"
+
+[dependencies]
diff --git a/sample_projects/integration_test_with_envvar/src/bin/exe-with-dash.rs b/sample_projects/integration_test_with_envvar/src/bin/exe-with-dash.rs
new file mode 100644
index 00000000..b3eb99d3
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/src/bin/exe-with-dash.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("exe-with-dash.rs");
+}
diff --git a/sample_projects/integration_test_with_envvar/src/bin/exe.rs b/sample_projects/integration_test_with_envvar/src/bin/exe.rs
new file mode 100644
index 00000000..8df69cee
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/src/bin/exe.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("exe.rs");
+}
diff --git a/sample_projects/integration_test_with_envvar/src/main.rs b/sample_projects/integration_test_with_envvar/src/main.rs
new file mode 100644
index 00000000..830a1658
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/src/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("main.rs");
+}
diff --git a/sample_projects/integration_test_with_envvar/test.nix b/sample_projects/integration_test_with_envvar/test.nix
new file mode 100644
index 00000000..580ae503
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/test.nix
@@ -0,0 +1,9 @@
+{ pkgs ? import ../../nix/nixpkgs.nix { config = { }; }
+, generatedCargoNix ? ./Cargo.nix { }
+}:
+let
+  instantiatedBuild = pkgs.callPackage generatedCargoNix { };
+in
+instantiatedBuild.rootCrate.build.override {
+  runTests = true;
+}
diff --git a/sample_projects/integration_test_with_envvar/tests/foo.rs b/sample_projects/integration_test_with_envvar/tests/foo.rs
new file mode 100644
index 00000000..752ca020
--- /dev/null
+++ b/sample_projects/integration_test_with_envvar/tests/foo.rs
@@ -0,0 +1,15 @@
+#[test]
+fn test_main() {
+  let mut cmd = std::process::Command::new(env!("CARGO_BIN_EXE_integration_test_with_envvar"));
+  assert_eq!(&cmd.output().unwrap().stdout, b"main.rs\n");
+}
+#[test]
+fn test_exe() {
+  let mut cmd = std::process::Command::new(env!("CARGO_BIN_EXE_exe"));
+  assert_eq!(&cmd.output().unwrap().stdout, b"exe.rs\n");
+}
+#[test]
+fn test_exe2() {
+  let mut cmd = std::process::Command::new(env!("CARGO_BIN_EXE_exe-with-dash"));
+  assert_eq!(&cmd.output().unwrap().stdout, b"exe-with-dash.rs\n");
+}
diff --git a/sample_projects/renamed_build_deps/result b/sample_projects/renamed_build_deps/result
deleted file mode 120000
index 78537b0d..00000000
--- a/sample_projects/renamed_build_deps/result
+++ /dev/null
@@ -1 +0,0 @@
-/nix/store/8lminniz3aj2dqxzx7hwfv2v0hzf3gqy-rust_rename_conflict-0.1.0
\ No newline at end of file
diff --git a/sample_projects/sub_dir_crates/Cargo.nix b/sample_projects/sub_dir_crates/Cargo.nix
index 52aaa247..d023d7e6 100644
--- a/sample_projects/sub_dir_crates/Cargo.nix
+++ b/sample_projects/sub_dir_crates/Cargo.nix
@@ -286,7 +286,10 @@ rec {
           let
             drv = testCrate.override (_: {
               buildTests = true;
-            });
+            } // (lib.optionalAttrs (testCrate ? testedCrate) {
+              # if nixpkgs is recent enough to support testedCrate, provide it
+              testedCrate = testCrate;
+            }));
             # If the user hasn't set any pre/post commands, we don't want to
             # insert empty lines. This means that any existing users of crate2nix
             # don't get a spurious rebuild unless they set these explicitly.
diff --git a/sample_projects/with_problematic_crates/Cargo.lock b/sample_projects/with_problematic_crates/Cargo.lock
index d4fb4743..34bbcbc8 100644
--- a/sample_projects/with_problematic_crates/Cargo.lock
+++ b/sample_projects/with_problematic_crates/Cargo.lock
@@ -1214,6 +1214,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "num-conv"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"
+
 [[package]]
 name = "num-traits"
 version = "0.2.17"
@@ -1831,12 +1837,13 @@ dependencies = [
 
 [[package]]
 name = "time"
-version = "0.3.31"
+version = "0.3.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f657ba42c3f86e7680e53c8cd3af8abbe56b5491790b46e22e19c0d57463583e"
+checksum = "ef89ece63debf11bc32d1ed8d078ac870cbeb44da02afb02a9ff135ae7ca0582"
 dependencies = [
  "deranged",
  "itoa",
+ "num-conv",
  "powerfmt",
  "serde",
  "time-core",
@@ -1851,10 +1858,11 @@ checksum = "ef927ca75afb808a4d64dd374f00a2adf8d0fcff8e7b184af886c3c87ec4a3f3"
 
 [[package]]
 name = "time-macros"
-version = "0.2.16"
+version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "26197e33420244aeb70c3e8c78376ca46571bc4e701e4791c2cd9f57dcb3a43f"
+checksum = "3f252a68540fde3a3877aeea552b832b40ab9a69e318efd078774a01ddee1ccf"
 dependencies = [
+ "num-conv",
  "time-core",
 ]
 
diff --git a/tests.nix b/tests.nix
index b244714b..ef90e94a 100644
--- a/tests.nix
+++ b/tests.nix
@@ -377,6 +377,20 @@ let
       ];
     }
 
+    {
+      name = "integration_test_with_envvar";
+      src = ./sample_projects/integration_test_with_envvar;
+      cargoToml = "Cargo.toml";
+      customBuild = "sample_projects/integration_test_with_envvar/test.nix";
+      expectedOutput = "main.rs";
+      expectedTestOutputs = [
+        "test test_exe ... ok"
+        "test test_exe2 ... ok"
+        "test test_main ... ok"
+
+      ];
+    }
+
     {
       name = "cross_compile_build_dependencies";
       src = ./sample_projects/cross_compile_build_dependencies;