Convert Exception#set_backtrace into a shared spec

This can be reused to test assignment of $@

Author: herwinw

core/exception/set_backtrace_spec.rb

@@ -1,13 +1,8 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/common'
+require_relative 'shared/set_backtrace'
 
 describe "Exception#set_backtrace" do
-  it "accepts an Array of Strings" do
-    err = RuntimeError.new
-    err.set_backtrace ["unhappy"]
-    err.backtrace.should == ["unhappy"]
-  end
-
   it "allows the user to set the backtrace from a rescued exception" do
     bt  = ExceptionSpecs::Backtrace.backtrace
     err = RuntimeError.new
@@ -20,65 +15,9 @@
     err.backtrace_locations.should == nil
   end
 
-  ruby_version_is "3.4" do
-    it "allows the user to set backtrace locations from a rescued exception" do
-      bt_locations = ExceptionSpecs::Backtrace.backtrace_locations
-      err = RuntimeError.new
-      err.backtrace.should == nil
-      err.backtrace_locations.should == nil
-
-      err.set_backtrace bt_locations
-
-      err.backtrace_locations.size.should == bt_locations.size
-      err.backtrace_locations.each_with_index do |loc, index|
-        other_loc = bt_locations[index]
-
-        loc.path.should == other_loc.path
-        loc.label.should == other_loc.label
-        loc.base_label.should == other_loc.base_label
-        loc.lineno.should == other_loc.lineno
-        loc.absolute_path.should == other_loc.absolute_path
-        loc.to_s.should == other_loc.to_s
-      end
-      err.backtrace.size.should == err.backtrace_locations.size
-    end
-  end
-
-  it "accepts an empty Array" do
-    err = RuntimeError.new
-    err.set_backtrace []
-    err.backtrace.should == []
-  end
-
-  it "accepts a String" do
+  it_behaves_like :exception_set_backtrace, ->(*backtrace) {
     err = RuntimeError.new
-    err.set_backtrace "unhappy"
-    err.backtrace.should == ["unhappy"]
-  end
-
-  it "accepts nil" do
-    err = RuntimeError.new
-    err.set_backtrace nil
-    err.backtrace.should be_nil
-  end
-
-  it "raises a TypeError when passed a Symbol" do
-    err = RuntimeError.new
-    -> { err.set_backtrace :unhappy }.should raise_error(TypeError)
-  end
-
-  it "raises a TypeError when the Array contains a Symbol" do
-    err = RuntimeError.new
-    -> { err.set_backtrace ["String", :unhappy] }.should raise_error(TypeError)
-  end
-
-  it "raises a TypeError when the array contains nil" do
-    err = Exception.new
-    -> { err.set_backtrace ["String", nil] }.should raise_error(TypeError)
-  end
-
-  it "raises a TypeError when the argument is a nested array" do
-    err = Exception.new
-    -> { err.set_backtrace ["String", ["String"]] }.should raise_error(TypeError)
-  end
+    err.set_backtrace(backtrace.first) unless backtrace.empty?
+    err
+  }
 end

core/exception/shared/set_backtrace.rb

@@ -0,0 +1,64 @@
+require_relative '../fixtures/common'
+
+describe :exception_set_backtrace, shared: true do
+  it "accepts an Array of Strings" do
+    err = @method.call(["unhappy"])
+    err.backtrace.should == ["unhappy"]
+  end
+
+  it "allows the user to set the backtrace from a rescued exception" do
+    bt  = ExceptionSpecs::Backtrace.backtrace
+    err = @method.call(bt)
+    err.backtrace.should == bt
+  end
+
+  ruby_version_is "3.4" do
+    it "allows the user to set backtrace locations from a rescued exception" do
+      bt_locations = ExceptionSpecs::Backtrace.backtrace_locations
+      err = @method.call(bt_locations)
+      err.backtrace_locations.size.should == bt_locations.size
+      err.backtrace_locations.each_with_index do |loc, index|
+        other_loc = bt_locations[index]
+
+        loc.path.should == other_loc.path
+        loc.label.should == other_loc.label
+        loc.base_label.should == other_loc.base_label
+        loc.lineno.should == other_loc.lineno
+        loc.absolute_path.should == other_loc.absolute_path
+        loc.to_s.should == other_loc.to_s
+      end
+      err.backtrace.size.should == err.backtrace_locations.size
+    end
+  end
+
+  it "accepts an empty Array" do
+    err = @method.call([])
+    err.backtrace.should == []
+  end
+
+  it "accepts a String" do
+    err = @method.call("unhappy")
+    err.backtrace.should == ["unhappy"]
+  end
+
+  it "accepts nil" do
+    err = @method.call(nil)
+    err.backtrace.should be_nil
+  end
+
+  it "raises a TypeError when passed a Symbol" do
+    -> { @method.call(:unhappy) }.should raise_error(TypeError)
+  end
+
+  it "raises a TypeError when the Array contains a Symbol" do
+    -> { @method.call(["String", :unhappy]) }.should raise_error(TypeError)
+  end
+
+  it "raises a TypeError when the array contains nil" do
+    -> { @method.call(["String", nil]) }.should raise_error(TypeError)
+  end
+
+  it "raises a TypeError when the argument is a nested array" do
+    -> { @method.call(["String", ["String"]]) }.should raise_error(TypeError)
+  end
+end