Add test for rustfmt with generated compile_data

Add a test case with an intentionally unformatted source file and
generated compile_data. This triggers transform_sources to symlink
sources into bazel-out, exercising the fix in _find_rustfmtable_srcs.

Without the fix, rustfmt silently passes (sources are skipped).
With the fix, rustfmt correctly detects the formatting issue.

Author: Tamas Vajk

test/rustfmt/rustfmt_failure_tester.sh

@@ -86,6 +86,7 @@ EOF
     check_build_result $TEST_OK ${variant}_formatted_2015_test
     check_build_result $TEST_OK ${variant}_formatted_2018_test
     check_build_result $TEST_OK ${variant}_generated_test
+    check_build_result $TEST_FAILED ${variant}_compile_data_generated_test
   done
 
   # Format a specific target
@@ -99,6 +100,7 @@ EOF
     check_build_result $TEST_OK ${variant}_formatted_2015_test
     check_build_result $TEST_OK ${variant}_formatted_2018_test
     check_build_result $TEST_OK ${variant}_generated_test
+    check_build_result $TEST_OK ${variant}_compile_data_generated_test
   done
 
   # Format all targets

test/rustfmt/rustfmt_integration_test_suite.bzl

@@ -1,5 +1,6 @@
 """Test definitions for rustfmt test rules"""
 
+load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load(
     "@rules_rust//rust:defs.bzl",
     "rust_binary",
@@ -101,12 +102,36 @@ def rustfmt_integration_test_suite(name, **kwargs):
             targets = [":{}_generated".format(variant)],
         )
 
+        #
+        # Test targets with generated compile_data (triggers transform_sources
+        # to symlink hand-written sources into bazel-out)
+        #
+        write_file(
+            name = "{}_compile_data_gen".format(variant),
+            out = "{}_generated_data.txt".format(variant),
+            content = ["generated"],
+        )
+
+        rust_rule(
+            name = "{}_compile_data_generated".format(variant),
+            srcs = ["srcs/compile_data_generated/lib.rs"],
+            compile_data = [":{}_compile_data_gen".format(variant)],
+            edition = "2021",
+        )
+
+        rustfmt_test(
+            name = "{}_compile_data_generated_test".format(variant),
+            tags = ["manual"],
+            targets = [":{}_compile_data_generated".format(variant)],
+        )
+
         tests.extend([
             "{}_formatted_2015_test".format(variant),
             "{}_formatted_2018_test".format(variant),
             "{}_unformatted_2015_test".format(variant),
             "{}_unformatted_2018_test".format(variant),
             "{}_generated_test".format(variant),
+            "{}_compile_data_generated_test".format(variant),
         ])
 
     native.test_suite(

test/rustfmt/srcs/compile_data_generated/lib.rs

@@ -0,0 +1,6 @@
+pub fn main()
+{
+    println!(
+        "compile_data_generated"
+    );
+}