Unify test venv python command creation (#14117)

Refactoring in preparation for
https://github.com/astral-sh/uv/pull/14080

crates/uv/tests/it/build.rs

@@ -7,7 +7,6 @@ use indoc::indoc;
 use insta::assert_snapshot;
 use predicates::prelude::predicate;
 use std::env::current_dir;
-use std::process::Command;
 use zip::ZipArchive;
 
 #[test]
@@ -1857,7 +1856,7 @@ fn build_unconfigured_setuptools() -> Result<()> {
      + greet==0.1.0 (from file://[TEMP_DIR]/)
     "###);
 
-    uv_snapshot!(context.filters(), Command::new(context.interpreter()).arg("-c").arg("import greet"), @r###"
+    uv_snapshot!(context.filters(), context.python_command().arg("-c").arg("import greet"), @r###"
     success: true
     exit_code: 0
     ----- stdout -----

crates/uv/tests/it/build_backend.rs

@@ -50,13 +50,9 @@ fn built_by_uv_direct_wheel() -> Result<()> {
         .assert()
         .success();
 
-    uv_snapshot!(context
+    uv_snapshot!(context.python_command()
-        .run()
-        .arg("python")
         .arg("-c")
-        .arg(BUILT_BY_UV_TEST_SCRIPT)
+        .arg(BUILT_BY_UV_TEST_SCRIPT), @r###"
-        // Python on windows
-        .env(EnvVars::PYTHONUTF8, "1"), @r###"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -138,13 +134,9 @@ fn built_by_uv_direct() -> Result<()> {
 
     drop(wheel_dir);
 
-    uv_snapshot!(context
+    uv_snapshot!(context.python_command()
-        .run()
-        .arg("python")
         .arg("-c")
-        .arg(BUILT_BY_UV_TEST_SCRIPT)
+        .arg(BUILT_BY_UV_TEST_SCRIPT), @r###"
-        // Python on windows
-        .env(EnvVars::PYTHONUTF8, "1"), @r###"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -169,7 +161,8 @@ fn built_by_uv_editable() -> Result<()> {
 
     // Without the editable, pytest fails.
     context.pip_install().arg("pytest").assert().success();
-    Command::new(context.interpreter())
+    context
+        .python_command()
         .arg("-m")
         .arg("pytest")
         .current_dir(built_by_uv)
@@ -200,7 +193,7 @@ fn built_by_uv_editable() -> Result<()> {
     drop(wheel_dir);
 
     // Now, pytest passes.
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-m")
         .arg("pytest")
         // Avoid showing absolute paths and column dependent layout
@@ -340,11 +333,9 @@ fn rename_module() -> Result<()> {
         .success();
 
     // Importing the module with the `module-name` name succeeds.
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-c")
-        .arg("import bar")
+        .arg("import bar"), @r###"
-        // Python on windows
-        .env(EnvVars::PYTHONUTF8, "1"), @r###"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -354,11 +345,9 @@ fn rename_module() -> Result<()> {
     "###);
 
     // Importing the package name fails, it was overridden by `module-name`.
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-c")
-        .arg("import foo")
+        .arg("import foo"), @r###"
-        // Python on windows
-        .env(EnvVars::PYTHONUTF8, "1"), @r###"
     success: false
     exit_code: 1
     ----- stdout -----
@@ -419,11 +408,9 @@ fn rename_module_editable_build() -> Result<()> {
         .success();
 
     // Importing the module with the `module-name` name succeeds.
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-c")
-        .arg("import bar")
+        .arg("import bar"), @r###"
-        // Python on windows
-        .env(EnvVars::PYTHONUTF8, "1"), @r###"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -514,11 +501,9 @@ fn build_module_name_normalization() -> Result<()> {
         .assert()
         .success();
 
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-c")
-        .arg("import Django_plugin")
+        .arg("import Django_plugin"), @r"
-        // Python on windows
-        .env(EnvVars::PYTHONUTF8, "1"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -728,7 +713,7 @@ fn complex_namespace_packages() -> Result<()> {
     "
     );
 
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-c")
         .arg("from complex_project.part_b import two; print(two())"),
         @r"
@@ -769,7 +754,7 @@ fn complex_namespace_packages() -> Result<()> {
     "
     );
 
-    uv_snapshot!(Command::new(context.interpreter())
+    uv_snapshot!(context.python_command()
         .arg("-c")
         .arg("from complex_project.part_b import two; print(two())"),
         @r"

crates/uv/tests/it/common/mod.rs

@@ -1085,15 +1085,30 @@ impl TestContext {
     }
 
     pub fn interpreter(&self) -> PathBuf {
-        venv_to_interpreter(&self.venv)
+        let venv = &self.venv;
+        if cfg!(unix) {
+            venv.join("bin").join("python")
+        } else if cfg!(windows) {
+            venv.join("Scripts").join("python.exe")
+        } else {
+            unimplemented!("Only Windows and Unix are supported")
+        }
+    }
+
+    pub fn python_command(&self) -> Command {
+        let mut command = self.new_command_with(&self.interpreter());
+        command
+            // Our tests change files in <1s, so we must disable CPython bytecode caching or we'll get stale files
+            // https://github.com/python/cpython/issues/75953
+            .arg("-B")
+            // Python on windows
+            .env(EnvVars::PYTHONUTF8, "1");
+        command
     }
 
     /// Run the given python code and check whether it succeeds.
     pub fn assert_command(&self, command: &str) -> Assert {
-        self.new_command_with(&venv_to_interpreter(&self.venv))
+        self.python_command()
-            // Our tests change files in <1s, so we must disable CPython bytecode caching or we'll get stale files
-            // https://github.com/python/cpython/issues/75953
-            .arg("-B")
             .arg("-c")
             .arg(command)
             .current_dir(&self.temp_dir)
@@ -1102,10 +1117,7 @@ impl TestContext {
 
     /// Run the given python file and check whether it succeeds.
     pub fn assert_file(&self, file: impl AsRef<Path>) -> Assert {
-        self.new_command_with(&venv_to_interpreter(&self.venv))
+        self.python_command()
-            // Our tests change files in <1s, so we must disable CPython bytecode caching or we'll get stale files
-            // https://github.com/python/cpython/issues/75953
-            .arg("-B")
             .arg(file.as_ref())
             .current_dir(&self.temp_dir)
             .assert()
@@ -1120,6 +1132,12 @@ impl TestContext {
         .stdout(version);
     }
 
+    /// Assert a package is not installed.
+    pub fn assert_not_installed(&self, package: &'static str) {
+        self.assert_command(format!("import {package}").as_str())
+            .failure();
+    }
+
     /// Generate various escaped regex patterns for the given path.
     pub fn path_patterns(path: impl AsRef<Path>) -> Vec<String> {
         let mut patterns = Vec::new();
@@ -1347,16 +1365,6 @@ pub fn venv_bin_path(venv: impl AsRef<Path>) -> PathBuf {
     }
 }
 
-pub fn venv_to_interpreter(venv: &Path) -> PathBuf {
-    if cfg!(unix) {
-        venv.join("bin").join("python")
-    } else if cfg!(windows) {
-        venv.join("Scripts").join("python.exe")
-    } else {
-        unimplemented!("Only Windows and Unix are supported")
-    }
-}
-
 /// Get the path to the python interpreter for a specific python version.
 pub fn get_python(version: &PythonVersion) -> PathBuf {
     ManagedPythonInstallations::from_settings(None)

crates/uv/tests/it/pip_install.rs

@@ -19,7 +19,7 @@ use wiremock::{
 use crate::common::{self, decode_token};
 use crate::common::{
     DEFAULT_PYTHON_VERSION, TestContext, build_vendor_links_url, download_to_disk, get_bin,
-    uv_snapshot, venv_bin_path, venv_to_interpreter,
+    uv_snapshot, venv_bin_path,
 };
 use uv_fs::Simplified;
 use uv_static::EnvVars;
@@ -9083,8 +9083,7 @@ fn build_tag() {
     );
 
     // Ensure that we choose the highest build tag (5).
-    uv_snapshot!(Command::new(venv_to_interpreter(&context.venv))
+    uv_snapshot!(context.python_command()
-        .arg("-B")
         .arg("-c")
         .arg("import build_tag; build_tag.main()")
         .current_dir(&context.temp_dir), @r###"

crates/uv/tests/it/pip_sync.rs

@@ -1,6 +1,4 @@
 use std::env::consts::EXE_SUFFIX;
-use std::path::Path;
-use std::process::Command;
 
 use anyhow::Result;
 use assert_cmd::prelude::*;
@@ -11,24 +9,10 @@ use indoc::indoc;
 use predicates::Predicate;
 use url::Url;
 
-use crate::common::{
+use crate::common::{TestContext, download_to_disk, site_packages_path, uv_snapshot};
-    TestContext, download_to_disk, site_packages_path, uv_snapshot, venv_to_interpreter,
-};
 use uv_fs::{Simplified, copy_dir_all};
 use uv_static::EnvVars;
 
-fn check_command(venv: &Path, command: &str, temp_dir: &Path) {
-    Command::new(venv_to_interpreter(venv))
-        // Our tests change files in <1s, so we must disable CPython bytecode caching or we'll get stale files
-        // https://github.com/python/cpython/issues/75953
-        .arg("-B")
-        .arg("-c")
-        .arg(command)
-        .current_dir(temp_dir)
-        .assert()
-        .success();
-}
-
 #[test]
 fn missing_requirements_txt() {
     let context = TestContext::new("3.12");
@@ -463,7 +447,13 @@ fn link() -> Result<()> {
     "###
     );
 
-    check_command(&context2.venv, "import iniconfig", &context2.temp_dir);
+    context2
+        .python_command()
+        .arg("-c")
+        .arg("import iniconfig")
+        .current_dir(&context2.temp_dir)
+        .assert()
+        .success();
 
     Ok(())
 }
@@ -5221,8 +5211,8 @@ fn target_built_distribution() -> Result<()> {
     context.assert_command("import iniconfig").failure();
 
     // Ensure that we can import the package by augmenting the `PYTHONPATH`.
-    Command::new(venv_to_interpreter(&context.venv))
+    context
-        .arg("-B")
+        .python_command()
         .arg("-c")
         .arg("import iniconfig")
         .env(EnvVars::PYTHONPATH, context.temp_dir.child("target").path())
@@ -5326,8 +5316,8 @@ fn target_source_distribution() -> Result<()> {
     context.assert_command("import iniconfig").failure();
 
     // Ensure that we can import the package by augmenting the `PYTHONPATH`.
-    Command::new(venv_to_interpreter(&context.venv))
+    context
-        .arg("-B")
+        .python_command()
         .arg("-c")
         .arg("import iniconfig")
         .env(EnvVars::PYTHONPATH, context.temp_dir.child("target").path())
@@ -5397,8 +5387,8 @@ fn target_no_build_isolation() -> Result<()> {
     context.assert_command("import wheel").failure();
 
     // Ensure that we can import the package by augmenting the `PYTHONPATH`.
-    Command::new(venv_to_interpreter(&context.venv))
+    context
-        .arg("-B")
+        .python_command()
         .arg("-c")
         .arg("import wheel")
         .env(EnvVars::PYTHONPATH, context.temp_dir.child("target").path())
@@ -5474,8 +5464,8 @@ fn prefix() -> Result<()> {
     context.assert_command("import iniconfig").failure();
 
     // Ensure that we can import the package by augmenting the `PYTHONPATH`.
-    Command::new(venv_to_interpreter(&context.venv))
+    context
-        .arg("-B")
+        .python_command()
         .arg("-c")
         .arg("import iniconfig")
         .env(

crates/uv/tests/it/pip_uninstall.rs

@@ -5,7 +5,7 @@ use assert_cmd::prelude::*;
 use assert_fs::fixture::ChildPath;
 use assert_fs::prelude::*;
 
-use crate::common::{TestContext, get_bin, uv_snapshot, venv_to_interpreter};
+use crate::common::{TestContext, get_bin, uv_snapshot};
 
 #[test]
 fn no_arguments() {
@@ -113,12 +113,7 @@ fn uninstall() -> Result<()> {
         .assert()
         .success();
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import markupsafe").success();
-        .arg("-c")
-        .arg("import markupsafe")
-        .current_dir(&context.temp_dir)
-        .assert()
-        .success();
 
     uv_snapshot!(context.pip_uninstall()
         .arg("MarkupSafe"), @r###"
@@ -132,12 +127,7 @@ fn uninstall() -> Result<()> {
     "###
     );
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import markupsafe").failure();
-        .arg("-c")
-        .arg("import markupsafe")
-        .current_dir(&context.temp_dir)
-        .assert()
-        .failure();
 
     Ok(())
 }
@@ -156,12 +146,7 @@ fn missing_record() -> Result<()> {
         .assert()
         .success();
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import markupsafe").success();
-        .arg("-c")
-        .arg("import markupsafe")
-        .current_dir(&context.temp_dir)
-        .assert()
-        .success();
 
     // Delete the RECORD file.
     let dist_info = context.site_packages().join("MarkupSafe-2.1.3.dist-info");
@@ -202,11 +187,7 @@ fn uninstall_editable_by_name() -> Result<()> {
         .assert()
         .success();
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import poetry_editable").success();
-        .arg("-c")
-        .arg("import poetry_editable")
-        .assert()
-        .success();
 
     // Uninstall the editable by name.
     uv_snapshot!(context.filters(), context.pip_uninstall()
@@ -221,11 +202,7 @@ fn uninstall_editable_by_name() -> Result<()> {
     "###
     );
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import poetry_editable").failure();
-        .arg("-c")
-        .arg("import poetry_editable")
-        .assert()
-        .failure();
 
     Ok(())
 }
@@ -251,11 +228,7 @@ fn uninstall_by_path() -> Result<()> {
         .assert()
         .success();
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import poetry_editable").success();
-        .arg("-c")
-        .arg("import poetry_editable")
-        .assert()
-        .success();
 
     // Uninstall the editable by path.
     uv_snapshot!(context.filters(), context.pip_uninstall()
@@ -270,11 +243,7 @@ fn uninstall_by_path() -> Result<()> {
     "###
     );
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import poetry_editable").failure();
-        .arg("-c")
-        .arg("import poetry_editable")
-        .assert()
-        .failure();
 
     Ok(())
 }
@@ -300,11 +269,7 @@ fn uninstall_duplicate_by_path() -> Result<()> {
         .assert()
         .success();
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import poetry_editable").success();
-        .arg("-c")
-        .arg("import poetry_editable")
-        .assert()
-        .success();
 
     // Uninstall the editable by both path and name.
     uv_snapshot!(context.filters(), context.pip_uninstall()
@@ -320,11 +285,7 @@ fn uninstall_duplicate_by_path() -> Result<()> {
     "###
     );
 
-    Command::new(venv_to_interpreter(&context.venv))
+    context.assert_command("import poetry_editable").failure();
-        .arg("-c")
-        .arg("import poetry_editable")
-        .assert()
-        .failure();
 
     Ok(())
 }

scripts/scenarios/templates/compile.mustache

@@ -16,8 +16,8 @@ use predicates::prelude::predicate;
 use uv_static::EnvVars;
 
 use crate::common::{
-    build_vendor_links_url, get_bin, packse_index_url, python_path_with_versions, uv_snapshot,
+    TestContext, build_vendor_links_url, get_bin, packse_index_url, python_path_with_versions,
-    TestContext,
+    uv_snapshot,
 };
 
 /// Provision python binaries and return a `pip compile` command with options shared across all scenarios.

scripts/scenarios/templates/install.mustache

@@ -5,52 +5,20 @@
 //!
 #![cfg(all(feature = "python", feature = "pypi", unix))]
 
-use std::path::Path;
 use std::process::Command;
 
-use assert_cmd::assert::Assert;
-use assert_cmd::prelude::*;
-
 use uv_static::EnvVars;
 
-use crate::common::{
+use crate::common::{TestContext, build_vendor_links_url, packse_index_url, uv_snapshot};
-    build_vendor_links_url, get_bin, packse_index_url, uv_snapshot, venv_to_interpreter,
-    TestContext,
-};
-
-fn assert_command(venv: &Path, command: &str, temp_dir: &Path) -> Assert {
-    Command::new(venv_to_interpreter(venv))
-        .arg("-c")
-        .arg(command)
-        .current_dir(temp_dir)
-        .assert()
-}
-
-fn assert_installed(venv: &Path, package: &'static str, version: &'static str, temp_dir: &Path) {
-    assert_command(
-        venv,
-        format!("import {package} as package; print(package.__version__, end='')").as_str(),
-        temp_dir,
-    )
-    .success()
-    .stdout(version);
-}
-
-fn assert_not_installed(venv: &Path, package: &'static str, temp_dir: &Path) {
-    assert_command(venv, format!("import {package}").as_str(), temp_dir).failure();
-}
 
 /// Create a `pip install` command with options shared across all scenarios.
 fn command(context: &TestContext) -> Command {
-    let mut command = Command::new(get_bin());
+    let mut command = context.pip_install();
     command
-        .arg("pip")
-        .arg("install")
         .arg("--index-url")
         .arg(packse_index_url())
         .arg("--find-links")
         .arg(build_vendor_links_url());
-    context.add_shared_options(&mut command, true);
     command.env_remove(EnvVars::UV_EXCLUDE_NEWER);
     command
 }
@@ -93,25 +61,20 @@ fn {{module_name}}() {
         {{/resolver_options.python_platform}}
         {{#root.requires}}
         .arg("{{requirement}}")
-        {{/root.requires}}, @r###"<snapshot>
+        {{/root.requires}}, @r#"<snapshot>
-    "###);
+    "#);
 
     {{#expected.explanation}}
     // {{expected.explanation}}
     {{/expected.explanation}}
     {{#expected.satisfiable}}
     {{#expected.packages}}
-    assert_installed(
+    context.assert_installed("{{module_name}}", "{{version}}");
-        &context.venv,
-        "{{module_name}}",
-        "{{version}}",
-        &context.temp_dir
-    );
     {{/expected.packages}}
     {{/expected.satisfiable}}
     {{^expected.satisfiable}}
     {{#root.requires}}
-    assert_not_installed(&context.venv, "{{module_name}}", &context.temp_dir);
+    context.assert_not_installed("{{module_name}}");
     {{/root.requires}}
     {{/expected.satisfiable}}
 }

scripts/scenarios/templates/lock.mustache

@@ -15,7 +15,7 @@ use insta::assert_snapshot;
 
 use uv_static::EnvVars;
 
-use crate::common::{packse_index_url, TestContext, uv_snapshot};
+use crate::common::{TestContext, packse_index_url, uv_snapshot};
 
 {{#scenarios}}