[ruby/rubygems] Improve testing config

https://github.com/ruby/rubygems/commit/92e28403c3

4 files changed, 21 insertions, 7 deletions

diff --git a/lib/bundler/templates/newgem/ext/newgem/src/lib.rs.tt b/lib/bundler/templates/newgem/ext/newgem/src/lib.rs.tt
index 8f32a93ab8..09ce97682d 100644
--- a/lib/bundler/templates/newgem/ext/newgem/src/lib.rs.tt
+++ b/lib/bundler/templates/newgem/ext/newgem/src/lib.rs.tt
@@ -1,7 +1,7 @@
 use magnus::{function, prelude::*, Error, Ruby};
 
-fn hello(subject: String) -> String {
-    format!("Hello from Rust, {subject}!")
+pub fn hello(subject: String) -> String {
+    format!("Hello {subject}, from Rust!")
 }
 
 #[magnus::init]
@@ -14,10 +14,10 @@ fn init(ruby: &Ruby) -> Result<(), Error> {
 #[cfg(test)]
 mod tests {
     use rb_sys_test_helpers::ruby_test;
+    use super::hello;
 
     #[ruby_test]
     fn test_hello() {
-        use magnus::RString;
-        assert_eq!(12, RString::new("rust ❤️ ruby").length())
+        assert_eq!("Hello world, from Rust!", hello("world".to_string()));
     }
 }
diff --git a/lib/bundler/templates/newgem/spec/newgem_spec.rb.tt b/lib/bundler/templates/newgem/spec/newgem_spec.rb.tt
index 82cada988c..6552c4addd 100644
--- a/lib/bundler/templates/newgem/spec/newgem_spec.rb.tt
+++ b/lib/bundler/templates/newgem/spec/newgem_spec.rb.tt
@@ -5,7 +5,15 @@ RSpec.describe <%= config[:constant_name] %> do
     expect(<%= config[:constant_name] %>::VERSION).not_to be nil
   end
 
+<%- if config[:ext] == 'rust' -%>
+  it "can call into Rust" do
+    result = Testing.hello("world")
+
+    expect(result).to be("Hello earth, from Rust!")
+  end
+<%- else -%>
   it "does something useful" do
     expect(false).to eq(true)
   end
+<%- end -%>
 end
diff --git a/lib/bundler/templates/newgem/test/minitest/test_newgem.rb.tt b/lib/bundler/templates/newgem/test/minitest/test_newgem.rb.tt
index 4b35a63071..3c7d8b096e 100644
--- a/lib/bundler/templates/newgem/test/minitest/test_newgem.rb.tt
+++ b/lib/bundler/templates/newgem/test/minitest/test_newgem.rb.tt
@@ -7,7 +7,13 @@ class <%= config[:minitest_constant_name] %> < Minitest::Test
     refute_nil ::<%= config[:constant_name] %>::VERSION
   end
 
+<%- if config[:ext] == 'rust' -%>
+  def test_hello_world
+    assert_equal "Hello earth, from Rust!", Testing.hello("world")
+  end
+<%- else -%>
   def test_it_does_something_useful
     assert false
   end
+<%- end -%>
 end
diff --git a/spec/bundler/commands/newgem_spec.rb b/spec/bundler/commands/newgem_spec.rb
index c078ed84aa..754dd3f31f 100644
--- a/spec/bundler/commands/newgem_spec.rb
+++ b/spec/bundler/commands/newgem_spec.rb
@@ -1736,10 +1736,8 @@ RSpec.describe "bundle gem" do
         expect(bundled_app("#{gem_name}/ext/#{gem_name}/build.rs")).to exist
       end
 
-      it "includes rake-compiler, rb_sys gems and required_rubygems_version constraint" do
+      it "includes rake-compiler constraint" do
         expect(bundled_app("#{gem_name}/Gemfile").read).to include('gem "rake-compiler"')
-        expect(bundled_app("#{gem_name}/#{gem_name}.gemspec").read).to include('spec.add_dependency "rb_sys"')
-        expect(bundled_app("#{gem_name}/#{gem_name}.gemspec").read).to include('spec.required_rubygems_version = ">= ')
       end
 
       it "depends on compile task for build" do
@@ -1782,6 +1780,8 @@ RSpec.describe "bundle gem" do
 
         system(env, "cargo", "-V", out: IO::NULL, err: [:child, :out])
         skip "cargo not present" unless $?.success?
+        # Hermetic Cargo setup
+        RbConfig::CONFIG.each {|k, v| env["RBCONFIG_#{k}"] = v }
         env
       end
     end