(subplotlib): Add a test for PATH prepending in Runcmd

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>

1 files changed, 75 insertions, 23 deletions

diff --git a/subplotlib/src/steplibrary/runcmd.rs b/subplotlib/src/steplibrary/runcmd.rs
index aee675e..8ed4f4f 100644
--- a/subplotlib/src/steplibrary/runcmd.rs
+++ b/subplotlib/src/steplibrary/runcmd.rs
@@ -6,10 +6,10 @@ pub use super::datadir::Datadir;
 pub use crate::prelude::*;
 
 use std::collections::HashMap;
-use std::env;
+use std::env::{self, JoinPathsError};
 use std::ffi::{OsStr, OsString};
 use std::io::Write;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 
 /// The Runcmd context gives a step function access to the ability to run
@@ -89,6 +89,76 @@ impl Runcmd {
     pub fn stderr_as_string(&self) -> String {
         String::from_utf8_lossy(&self.stderr).into_owned()
     }
+
+    /// Set an env var in the Runcmd context
+    ///
+    /// This sets an environment variable into the Runcmd context for use
+    /// during execution
+    pub fn setenv<K: Into<OsString>, V: Into<OsString>>(&mut self, key: K, value: V) {
+        self.env.insert(key.into(), value.into());
+    }
+
+    /// Get an env var from the Runcmd context
+    ///
+    /// This retrieves a set environment variable from the Runcmd context
+    pub fn getenv<K: AsRef<OsStr>>(&self, key: K) -> Option<&OsStr> {
+        self.env.get(key.as_ref()).map(OsString::as_os_str)
+    }
+
+    /// Unset an env var in the Runcmd context
+    ///
+    /// This removes an environment variable (if set) from the Runcmd context
+    /// and returns whether or not it was removed.
+    pub fn unsetenv<K: AsRef<OsStr>>(&mut self, key: K) -> bool {
+        self.env.remove(key.as_ref()).is_some()
+    }
+
+    /// Join the `PATH` environment variable and the `paths` attribute
+    /// together properly.
+    ///
+    /// This prepends the paths (in reverse order) to the `PATH` environment
+    /// variable and then returns it.
+    ///
+    /// If there is no `PATH` in the stored environment then the resultant
+    /// path will be entirely made up of the pushed path elements
+    ///
+    /// ```
+    /// # use subplotlib::steplibrary::runcmd::Runcmd;
+    ///
+    /// let mut rc = Runcmd::default();
+    ///
+    /// assert_eq!(rc.join_paths().unwrap(), "");
+    ///
+    /// rc.setenv("PATH", "one");
+    /// assert_eq!(rc.join_paths().unwrap(), "one");
+    ///
+    /// rc.prepend_to_path("two");
+    /// assert_eq!(rc.join_paths().unwrap(), "two:one");
+    ///
+    /// rc.unsetenv("PATH");
+    /// assert_eq!(rc.join_paths().unwrap(), "two");
+    ///
+    /// rc.prepend_to_path("three");
+    /// assert_eq!(rc.join_paths().unwrap(), "three:two");
+    ///
+    /// rc.setenv("PATH", "one");
+    /// assert_eq!(rc.join_paths().unwrap(), "three:two:one");
+    /// ```
+    ///
+    pub fn join_paths(&self) -> Result<OsString, JoinPathsError> {
+        let curpath = self
+            .env
+            .get(OsStr::new("PATH"))
+            .map(|s| s.as_os_str())
+            .unwrap_or_else(|| OsStr::new(""));
+        env::join_paths(
+            self.paths
+                .iter()
+                .rev()
+                .map(PathBuf::from)
+                .chain(env::split_paths(curpath).filter(|p| p != Path::new(""))),
+        )
+    }
 }
 
 /// Ensure the given data file is available as a script in the data dir
@@ -196,35 +266,17 @@ pub fn try_to_run_in(context: &ScenarioContext, dirname: &str, argv0: &str, args
     proc.env("HOME", &datadir);
     proc.env("TMPDIR", &datadir);
 
-    let mut curpath = context.with(
+    context.with(
         |runcmd: &Runcmd| {
-            let mut curpath = None;
             for (k, v) in runcmd.env.iter() {
                 proc.env(k, v);
-                if k == "PATH" {
-                    curpath = Some(v.to_owned());
-                }
             }
-            Ok(curpath)
+            Ok(())
         },
         false,
     )?;
 
-    let path = context.with(
-        |runcmd: &Runcmd| {
-            Ok(env::join_paths(
-                runcmd
-                    .paths
-                    .iter()
-                    .rev()
-                    .map(PathBuf::from)
-                    .chain(env::split_paths(
-                        curpath.as_deref().unwrap_or_else(|| OsStr::new("")),
-                    )),
-            )?)
-        },
-        false,
-    )?;
+    let path = context.with(|runcmd: &Runcmd| Ok(runcmd.join_paths()?), false)?;
     proc.env("PATH", path);
     proc.stdin(Stdio::null())
         .stdout(Stdio::piped())