extracted boolean validation logic into stand-alone validator

spec/models/code_ocean/file_spec.rb

@@ -9,6 +9,8 @@ describe CodeOcean::File do
 
   it 'validates the presence of the hidden flag' do
     expect(file.errors[:hidden]).to be_present
+    file.update(hidden: false)
+    expect(file.errors[:hidden]).to be_blank
   end
 
   it 'validates the presence of a name' do
@@ -17,6 +19,8 @@ describe CodeOcean::File do
 
   it 'validates the presence of the read-only flag' do
     expect(file.errors[:read_only]).to be_present
+    file.update(read_only: false)
+    expect(file.errors[:read_only]).to be_blank
   end
 
   context 'as a teacher-defined test' do

spec/models/execution_environment_spec.rb

@@ -34,6 +34,8 @@ describe ExecutionEnvironment do
 
   it 'validates the presence of the network enabled flag' do
     expect(execution_environment.errors[:network_enabled]).to be_present
+    execution_environment.update(network_enabled: false)
+    expect(execution_environment.errors[:network_enabled]).to be_blank
   end
 
   it 'validates the numericality of the permitted run time' do

spec/models/exercise_spec.rb

@@ -28,6 +28,8 @@ describe Exercise do
 
   it 'validates the presence of the public flag' do
     expect(exercise.errors[:public]).to be_present
+    exercise.update(public: false)
+    expect(exercise.errors[:public]).to be_blank
   end
 
   it 'validates the presence of a title' do

spec/models/file_type_spec.rb

@@ -5,6 +5,8 @@ describe FileType do
 
   it 'validates the presence of the binary flag' do
     expect(file_type.errors[:binary]).to be_present
+    file_type.update(binary: false)
+    expect(file_type.errors[:binary]).to be_blank
   end
 
   context 'when binary' do
@@ -33,6 +35,8 @@ describe FileType do
 
   it 'validates the presence of the executable flag' do
     expect(file_type.errors[:executable]).to be_present
+    file_type.update(executable: false)
+    expect(file_type.errors[:executable]).to be_blank
   end
 
   it 'validates the presence of a name' do
@@ -41,6 +45,8 @@ describe FileType do
 
   it 'validates the presence of the renderable flag' do
     expect(file_type.errors[:renderable]).to be_present
+    file_type.update(renderable: false)
+    expect(file_type.errors[:renderable]).to be_blank
   end
 
   it 'validates the presence of a user' do