refactor(test): implement new testing DSL and simple showcase

Author: rami3l

Cargo.lock

@@ -37,7 +37,7 @@ otel = [
 ]
 
 # Exports code dependent on private interfaces for the integration test suite
-test = ["dep:walkdir"]
+test = ["dep:snapbox", "dep:walkdir"]
 
 # Sorted by alphabetic order
 [dependencies]
@@ -77,6 +77,7 @@ semver = "1.0"
 serde = { version = "1.0", features = ["derive"] }
 sha2 = "0.10"
 sharded-slab = "0.1.1"
+snapbox = { version = "0.6.21", optional = true }
 strsim = "0.11"
 tar = "0.4.26"
 tempfile = "3.8"

Cargo.toml

@@ -18,6 +18,7 @@ use std::{
 };
 
 use enum_map::{Enum, EnumMap, enum_map};
+use snapbox::{IntoData, assert_data_eq};
 use tempfile::TempDir;
 use url::Url;
 
@@ -61,6 +62,33 @@ pub struct Config {
     pub test_root_dir: PathBuf,
 }
 
+#[must_use]
+pub struct Assert {
+    output: SanitizedOutput,
+}
+
+impl Assert {
+    pub fn is_ok(&self) -> &Self {
+        assert!(self.output.ok);
+        self
+    }
+
+    pub fn is_err(&self) -> &Self {
+        assert!(!self.output.ok);
+        self
+    }
+
+    pub fn with_stdout(&self, expected: impl IntoData) -> &Self {
+        assert_data_eq!(&self.output.stdout, expected);
+        self
+    }
+
+    pub fn with_stderr(&self, expected: impl IntoData) -> &Self {
+        assert_data_eq!(&self.output.stderr, expected);
+        self
+    }
+}
+
 impl Config {
     pub fn current_dir(&self) -> PathBuf {
         self.workdir.borrow().clone()
@@ -136,6 +164,20 @@ impl Config {
         }
     }
 
+    pub async fn expect_with_env(
+        &self,
+        args: impl AsRef<[&str]>,
+        env: impl AsRef<[(&str, &str)]>,
+    ) -> Assert {
+        let args = args.as_ref();
+        let output = self.run(args[0], &args[1..], env.as_ref()).await;
+        Assert { output }
+    }
+
+    pub async fn expect(&self, args: impl AsRef<[&str]>) -> Assert {
+        self.expect_with_env(args, &[]).await
+    }
+
     /// Expect an ok status
     pub async fn expect_ok(&mut self, args: &[&str]) {
         self.expect_ok_env(args, &[]).await

src/test/clitools.rs

@@ -5,16 +5,16 @@ use std::fs;
 
 use rustup::for_host;
 use rustup::test::{CliTestContext, Scenario};
+use snapbox::str;
 
 #[tokio::test]
 async fn rustc_no_default_toolchain() {
     let cx = CliTestContext::new(Scenario::SimpleV1).await;
     cx.config
-        .expect_err(
-            &["rustc"],
-            "rustup could not choose a version of rustc to run",
-        )
-        .await;
+        .expect(["rustc"])
+        .await
+        .is_err()
+        .with_stderr(str!["rustup could not choose a version of rustc to run"]);
 }
 
 #[tokio::test]