add parse package to parse csv files

parser/parser.go

@@ -0,0 +1,42 @@
+package parser
+
+import (
+	"bufio"
+	"encoding/csv"
+	"io"
+	"os"
+)
+
+type Site struct {
+	Name string
+	URL  string
+}
+
+func Parse(file string) ([]*Site, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+
+	r := csv.NewReader(bufio.NewReader(f))
+	return parse(r)
+}
+
+func parse(r *csv.Reader) ([]*Site, error) {
+	var sites []*Site
+
+	for {
+		line, err := r.Read()
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			return nil, err
+		}
+
+		sites = append(sites, &Site{Name: line[0], URL: line[1]})
+	}
+
+	return sites, nil
+}

parser/parser_test.go

@@ -0,0 +1,73 @@
+package parser
+
+import (
+	"encoding/csv"
+	"strings"
+	"testing"
+)
+
+func TestParse(t *testing.T) {
+	tt := []struct {
+		name           string
+		input          string
+		expectedResult []*Site
+	}{
+		{
+			name:  "one line",
+			input: "500px,https://500px.com/",
+			expectedResult: []*Site{
+				{
+					Name: "500px",
+					URL:  "https://500px.com/",
+				},
+			},
+		},
+		{
+			name:  "multiple lines",
+			input: "500px,https://500px.com/\nGoogle,https://google.com\nGitHub,https://github.com",
+			expectedResult: []*Site{
+				{
+					Name: "500px",
+					URL:  "https://500px.com/",
+				},
+				{
+					Name: "Google",
+					URL:  "https://google.com",
+				},
+				{
+					Name: "GitHub",
+					URL:  "https://github.com",
+				},
+			},
+		},
+		{
+			name:           "empty",
+			input:          "",
+			expectedResult: []*Site{},
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			r := csv.NewReader(strings.NewReader(tc.input))
+			sites, err := parse(r)
+			if err != nil {
+				t.Fatalf("while parsing csv input: %v", err)
+			}
+
+			if len(sites) != len(tc.expectedResult) {
+				t.Fatalf("expected len of parsed sites to be %v. got=%v", len(tc.expectedResult), len(sites))
+			}
+
+			for i, es := range tc.expectedResult {
+				if sites[i].Name != es.Name {
+					t.Fatalf("expected a parsed site called %q. got a site called %q", es.Name, sites[i].Name)
+				}
+
+				if sites[i].URL != es.URL {
+					t.Fatalf("expected a parsed site with URL %q. got a site with URL %q", es.URL, sites[i].URL)
+				}
+			}
+		})
+	}
+}