Merge pull request #24 from tendermint/dateparse

common date parsing

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Develop-Branch changes (unreleased)
+
+FEATURES:
+
+- [common] Date range parsing from string (ex. "2015-12-31:2017-12-31") 
+
 ## 0.2.2 (June 16, 2017)
 
 FEATURES:
@@ -16,7 +22,6 @@ BUG FIXES:
 
 - [flowrate] Fix non-deterministic test failures
 
-
 ## 0.2.1 (June 2, 2017)
 
 FEATURES:

common/date.go

@@ -0,0 +1,43 @@
+package common
+
+import (
+	"strings"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+// TimeLayout helps to parse a date string of the format YYYY-MM-DD
+//   Intended to be used with the following function:
+// 	 time.Parse(TimeLayout, date)
+var TimeLayout = "2006-01-02" //this represents YYYY-MM-DD
+
+// ParseDateRange parses a date range string of the format start:end
+//   where the start and end date are of the format YYYY-MM-DD.
+//   The parsed dates are time.Time and will return the zero time for
+//   unbounded dates, ex:
+//   unbounded start:	:2000-12-31
+//	 unbounded end: 	2000-12-31:
+func ParseDateRange(dateRange string) (startDate, endDate time.Time, err error) {
+	dates := strings.Split(dateRange, ":")
+	if len(dates) != 2 {
+		err = errors.New("bad date range, must be in format date:date")
+		return
+	}
+	parseDate := func(date string) (out time.Time, err error) {
+		if len(date) == 0 {
+			return
+		}
+		out, err = time.Parse(TimeLayout, date)
+		return
+	}
+	startDate, err = parseDate(dates[0])
+	if err != nil {
+		return
+	}
+	endDate, err = parseDate(dates[1])
+	if err != nil {
+		return
+	}
+	return
+}

common/date_test.go

@@ -0,0 +1,46 @@
+package common
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	date  = time.Date(2015, time.Month(12), 31, 0, 0, 0, 0, time.UTC)
+	date2 = time.Date(2016, time.Month(12), 31, 0, 0, 0, 0, time.UTC)
+	zero  time.Time
+)
+
+func TestParseDateRange(t *testing.T) {
+	assert := assert.New(t)
+
+	var testDates = []struct {
+		dateStr string
+		start   time.Time
+		end     time.Time
+		errNil  bool
+	}{
+		{"2015-12-31:2016-12-31", date, date2, true},
+		{"2015-12-31:", date, zero, true},
+		{":2016-12-31", zero, date2, true},
+		{"2016-12-31", zero, zero, false},
+		{"2016-31-12:", zero, zero, false},
+		{":2016-31-12", zero, zero, false},
+	}
+
+	for _, test := range testDates {
+		start, end, err := ParseDateRange(test.dateStr)
+		if test.errNil {
+			assert.Nil(err)
+			testPtr := func(want, have time.Time) {
+				assert.True(have.Equal(want))
+			}
+			testPtr(test.start, start)
+			testPtr(test.end, end)
+		} else {
+			assert.NotNil(err)
+		}
+	}
+}