Do not run formats_source if rustfmt is not available

Generalized `clippy_is_available` and renamed as `command_is_available`.

No checks in `ignores_failure_to_format_source`, it's not supposed to
use `rustfmt` even if it's available

Author: Kinrany

crates/cargo-test-support/src/lib.rs

@@ -1801,9 +1801,9 @@ pub fn slow_cpu_multiplier(main: u64) -> Duration {
     Duration::from_secs(*SLOW_CPU_MULTIPLIER * main)
 }
 
-pub fn clippy_is_available() -> bool {
-    if let Err(e) = process("clippy-driver").arg("-V").exec_with_output() {
-        eprintln!("clippy-driver not available, skipping clippy test");
+pub fn command_is_available(cmd: &str) -> bool {
+    if let Err(e) = process(cmd).arg("-V").exec_with_output() {
+        eprintln!("{} not available, skipping tests", cmd);
         eprintln!("{:?}", e);
         false
     } else {

tests/testsuite/cache_messages.rs

@@ -1,7 +1,7 @@
 //! Tests for caching compiler diagnostics.
 
 use cargo_test_support::{
-    basic_manifest, clippy_is_available, is_coarse_mtime, process, project, registry::Package,
+    basic_manifest, command_is_available, is_coarse_mtime, process, project, registry::Package,
     sleep_ms,
 };
 use std::path::Path;
@@ -276,7 +276,7 @@ fn fix() {
 
 #[cargo_test]
 fn clippy() {
-    if !clippy_is_available() {
+    if !command_is_available("clippy-driver") {
         return;
     }
 

tests/testsuite/clippy.rs

@@ -1,11 +1,11 @@
 //! Tests for the `cargo clippy` command.
 
-use cargo_test_support::{clippy_is_available, project, registry::Package};
+use cargo_test_support::{command_is_available, project, registry::Package};
 
 #[cargo_test]
 // Clippy should never be considered fresh.
 fn clippy_force_rebuild() {
-    if !clippy_is_available() {
+    if !command_is_available("clippy-driver") {
         return;
     }
 
@@ -43,7 +43,7 @@ fn clippy_force_rebuild() {
 
 #[cargo_test]
 fn clippy_passes_args() {
-    if !clippy_is_available() {
+    if !command_is_available("clippy-driver") {
         return;
     }
 

tests/testsuite/fix.rs

@@ -3,7 +3,7 @@
 use std::fs::File;
 
 use cargo_test_support::git;
-use cargo_test_support::{basic_manifest, clippy_is_available, project};
+use cargo_test_support::{basic_manifest, command_is_available, project};
 
 use std::io::Write;
 
@@ -1253,7 +1253,7 @@ fn fix_in_existing_repo_weird_ignore() {
 
 #[cargo_test]
 fn fix_with_clippy() {
-    if !clippy_is_available() {
+    if !command_is_available("clippy-driver") {
         return;
     }
 

tests/testsuite/init.rs

@@ -6,7 +6,7 @@ use std::fs::{self, File};
 use std::io::prelude::*;
 use std::process::Command;
 
-use cargo_test_support::{paths, Execs};
+use cargo_test_support::{command_is_available, paths, Execs};
 
 fn cargo_process(s: &str) -> Execs {
     let mut execs = cargo_test_support::cargo_process(s);
@@ -660,6 +660,10 @@ fn no_filename() {
 
 #[cargo_test]
 fn formats_source() {
+    if !command_is_available("rustfmt") {
+        return;
+    }
+
     fs::write(&paths::root().join("rustfmt.toml"), "tab_spaces = 2").unwrap();
 
     cargo_process("init --lib")