diff --git a/README.md b/README.md
new file mode 100644
index 0000000..792d600
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+#
diff --git a/analyse.go b/analyse.go
index a5903ac..72f4658 100644
--- a/analyse.go
+++ b/analyse.go
@@ -2,6 +2,7 @@ package redhat
 
 import (
 	"bufio"
+	"fmt"
 	"os"
 	"sort"
 	"strings"
@@ -17,7 +18,7 @@ func (fa *FileAnalyser) AnalyseData() error {
 		return err
 	}
 
-	fa.transformToDataRows(contentMap)
+	fa.transformFromMapToDataRows(contentMap)
 	fa.sortDataRows()
 
 	return nil
@@ -25,6 +26,7 @@ func (fa *FileAnalyser) AnalyseData() error {
 
 func (fa *FileAnalyser) parseContent(file *os.File, handler HandleLine) (map[string]int, error) {
 	contentMap := make(map[string]int)
+
 	scanner := bufio.NewScanner(file)
 
 	defer file.Close()
@@ -34,7 +36,7 @@ func (fa *FileAnalyser) parseContent(file *os.File, handler HandleLine) (map[str
 	}
 
 	if err := scanner.Err(); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("fail to read and process content: %s", err.Error())
 	}
 	return contentMap, nil
 }
@@ -44,11 +46,11 @@ func (fa *FileAnalyser) sortDataRows() {
 		if firstItemHasMoreCount(fa, i, j) {
 			return true
 		}
-		return compareRowsWhenSameCount(fa, i, j)
+		return compareRowsWhenAreSameCount(fa, i, j)
 	})
 }
 
-func (fa *FileAnalyser) transformToDataRows(contentMap map[string]int) {
+func (fa *FileAnalyser) transformFromMapToDataRows(contentMap map[string]int) {
 	for key, value := range contentMap {
 		fa.dataRows = append(fa.dataRows, dataRow{
 			word:  key,
@@ -73,6 +75,6 @@ func firstItemHasMoreCount(fa *FileAnalyser, i int, j int) bool {
 	return fa.dataRows[i].count > fa.dataRows[j].count
 }
 
-func compareRowsWhenSameCount(fa *FileAnalyser, i int, j int) bool {
+func compareRowsWhenAreSameCount(fa *FileAnalyser, i int, j int) bool {
 	return (fa.dataRows[i].count == fa.dataRows[j].count) && fa.dataRows[i].word > fa.dataRows[j].word
 }
diff --git a/cmd/main.go b/cmd/main.go
index aa9bff0..e13acf2 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -13,9 +13,7 @@ const defaultTopLines = 10
 func main() {
 	args := os.Args
 	if len(args) < 2 || len(args) > 3 {
-		panic(
-			`Please specify valid parameters: go run main.go [file path] [number of top lines]
-e.g. go run main.go abc/def.txt or go run main.go abc/def.txt 10 `)
+		panic(`Usage: go run main.go [file path] [number of top lines]`)
 	}
 
 	filepath := args[1]
diff --git a/print.go b/print.go
index a449c54..e5d79c7 100644
--- a/print.go
+++ b/print.go
@@ -4,10 +4,17 @@ import "fmt"
 
 // Output print out the result with target format
 func (fa *FileAnalyser) Output(topLines int) []string {
-	resultRows := fa.dataRows[0:topLines]
+	var resultRows []dataRow
+
+	if len(fa.dataRows) < 10 {
+		resultRows = fa.dataRows[0:len(fa.dataRows)]
+	} else {
+		resultRows = fa.dataRows[0:topLines]
+	}
+
 	reverseDataRows(resultRows)
 
-	outputArray := make([]string,0, len(resultRows))
+	outputArray := make([]string, 0, len(resultRows))
 
 	for index := 0; index < len(resultRows); index++ {
 		outputArray = append(outputArray, fmt.Sprintf("%d %s", resultRows[index].count, resultRows[index].word))
diff --git a/print_test.go b/print_test.go
new file mode 100644
index 0000000..e1d93b1
--- /dev/null
+++ b/print_test.go
@@ -0,0 +1,142 @@
+package redhat
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFileAnalyser_Output(t *testing.T) {
+	type args struct {
+		topLines int
+	}
+
+	tests := []struct {
+		name         string
+		fileAnalyser *FileAnalyser
+		args         args
+		want         []string
+	}{
+		{
+			name: "should reverse and only return top 10 items, as well as transform to output style",
+			fileAnalyser: &FileAnalyser{
+				file: nil,
+				dataRows: []dataRow{
+					{
+						word:  "and",
+						count: 9,
+					},
+					{
+						word:  "hello",
+						count: 9,
+					},
+					{
+						word:  "Go",
+						count: 7,
+					},
+					{
+						word:  "me",
+						count: 7,
+					},
+					{
+						word:  "the",
+						count: 6,
+					},
+					{
+						word:  "of",
+						count: 6,
+					},
+					{
+						word:  "shape",
+						count: 5,
+					},
+					{
+						word:  "libraries",
+						count: 4,
+					},
+					{
+						word:  "future",
+						count: 3,
+					},
+					{
+						word:  "Some",
+						count: 2,
+					},
+					{
+						word:  "Help",
+						count: 1,
+					},
+				},
+			},
+			args: args{
+				topLines: 10,
+			},
+			want: []string{
+				"2 Some",
+				"3 future",
+				"4 libraries",
+				"5 shape",
+				"6 of",
+				"6 the",
+				"7 me",
+				"7 Go",
+				"9 hello",
+				"9 and",
+			},
+		},
+		{
+			name: "should reverse and return all items when total items count is less than 10",
+			fileAnalyser: &FileAnalyser{
+				file: nil,
+				dataRows: []dataRow{
+					{
+						word:  "the",
+						count: 6,
+					},
+					{
+						word:  "of",
+						count: 6,
+					},
+					{
+						word:  "shape",
+						count: 5,
+					},
+					{
+						word:  "libraries",
+						count: 4,
+					},
+					{
+						word:  "future",
+						count: 3,
+					},
+					{
+						word:  "Some",
+						count: 2,
+					},
+					{
+						word:  "Help",
+						count: 1,
+					},
+				},
+			},
+			args: args{
+				topLines: 10,
+			},
+			want: []string{
+				"1 Help",
+				"2 Some",
+				"3 future",
+				"4 libraries",
+				"5 shape",
+				"6 of",
+				"6 the",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.fileAnalyser.Output(tt.args.topLines); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("FileAnalyser.Output() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}