fix file chunk arg validation

Author: ryan-avamia

lib/kanrisuru/core/stream.rb

@@ -35,8 +35,8 @@ def tail(path, opts = {})
       end
 
       def read_file_chunk(path, start_line, end_line)
-        if start_line.instance_of?(Integer) || end_line.instance_of?(Integer) ||
-           start_line > end_line || start_line.negative?
+        if !start_line.instance_of?(Integer) || !end_line.instance_of?(Integer) ||
+           start_line > end_line || start_line.negative? || end_line.negative?
           raise ArgumentError, 'Invalid start or end'
         end
 

spec/functional/core/stream_spec.rb

@@ -74,6 +74,24 @@
         expect(result.data).to eq(['a', 'file!'])
       end
 
+      it 'reads a chunk of text from a file' do
+        file = host.file("#{spec_dir}/test-file-chunk.txt")
+        file.touch
+        file.append do |f|
+          f << 'This'
+          f << 'is'
+          f << 'is'
+          f << 'a'
+          f << 'file'
+          f << 'forever...'
+        end
+
+        result = host.read_file_chunk("#{spec_dir}/test-file-chunk.txt", 2, 4)
+        expect(result).to be_success
+        expect(result.data.length).to eq(3)
+        expect(result.data).to eq(['is', 'is', 'a'])
+      end
+
       it 'cats a file' do
         result = host.cat('/etc/group')
         expect(result.success?).to eq(true)