Raise error when Coverage.start called repeatedly

Author: andrykonchin

lib/truffle/coverage.rb

@@ -17,6 +17,10 @@ def self.supported?(mode)
   end
 
   def self.start(modes = UNDEFINED)
+    if Truffle::Coverage.enabled?
+      raise 'coverage measurement is already setup'
+    end
+
     if modes == :all || modes == UNDEFINED
       options = {}
     else
@@ -46,6 +50,7 @@ def self.result(stop: true, clear: true)
         { lines: lines_array.unshift(nil) }
       end
     end
+
     result
   end
 

spec/ruby/library/coverage/result_spec.rb

@@ -75,17 +75,6 @@
     end
   end
 
-  ruby_version_is '3.1' do
-    it 'second Coverage.start give exception' do
-      Coverage.start
-      -> {
-        require @config_file.chomp('.rb')
-      }.should raise_error(RuntimeError, 'coverage measurement is already setup')
-    ensure
-      Coverage.result
-    end
-  end
-
   it 'does not include the file starting coverage since it is not tracked' do
     require @config_file.chomp('.rb')
     Coverage.result.should_not include(@config_file)
@@ -124,7 +113,7 @@
       }
     end
 
-    it 'returns the correct results when eval coverage is enabled' do
+    it 'returns the correct results when eval coverage is disabled' do
       Coverage.supported?(:eval).should == true
 
       Coverage.start(lines: true, eval: false)

spec/ruby/library/coverage/start_spec.rb

@@ -19,6 +19,16 @@
     Coverage.start.should == nil
   end
 
+  ruby_version_is '3.1' do
+    it 'raises error when repeated Coverage.start call happens' do
+      Coverage.start
+
+      -> {
+        Coverage.start
+      }.should raise_error(RuntimeError, 'coverage measurement is already setup')
+    end
+  end
+
   ruby_version_is '3.2' do
     it "accepts :all optional argument" do
       Coverage.start(:all)

spec/tags/library/coverage/result_tags.txt

@@ -1,3 +1,4 @@
 fails:Coverage.result second Coverage.start give exception
 fails:Coverage.result indicates support for different features
 fails:Coverage.result returns the correct results when eval coverage is enabled
+fails:Coverage.result returns the correct results when eval coverage is disabled