Add go/gigasecond

go/gigasecond/README.md

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+# Gigasecond
+
+Calculate the moment when someone has lived for 10^9 seconds.
+
+A gigasecond is 10^9 (1,000,000,000) seconds.
+
+## Running the tests
+
+To run the tests run the command `go test` from within the exercise directory.
+
+If the test suite contains benchmarks, you can run these with the `--bench` and `--benchmem`
+flags:
+
+    go test -v --bench . --benchmem
+
+Keep in mind that each reviewer will run benchmarks on a different machine, with
+different specs, so the results from these benchmark tests may vary.
+
+## Further information
+
+For more detailed information about the Go track, including how to get help if
+you're having trouble, please visit the exercism.io [Go language page](http://exercism.io/languages/go/resources).
+
+## Source
+
+Chapter 9 in Chris Pine's online Learn to Program tutorial. [http://pine.fm/LearnToProgram/?Chapter=09](http://pine.fm/LearnToProgram/?Chapter=09)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

go/gigasecond/cases_test.go

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+package gigasecond
+
+// Source: exercism/problem-specifications
+// Commit: 5506bac gigasecond: Apply new "input" policy
+// Problem Specifications Version: 1.1.0
+
+// Add one gigasecond to the input.
+var addCases = []struct {
+	description string
+	in          string
+	want        string
+}{
+	{
+		"date only specification of time",
+		"2011-04-25",
+		"2043-01-01T01:46:40",
+	},
+	{
+		"second test for date only specification of time",
+		"1977-06-13",
+		"2009-02-19T01:46:40",
+	},
+	{
+		"third test for date only specification of time",
+		"1959-07-19",
+		"1991-03-27T01:46:40",
+	},
+	{
+		"full time specified",
+		"2015-01-24T22:00:00",
+		"2046-10-02T23:46:40",
+	},
+	{
+		"full time with day roll-over",
+		"2015-01-24T23:59:59",
+		"2046-10-03T01:46:39",
+	},
+}

go/gigasecond/gigasecond.go

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+// Package gigasecond provides functions that modify time by gigasecond values.
+package gigasecond
+
+import "time"
+
+// AddGigasecond returns a time that is one gigasecond into the future from the
+// input time, t.
+func AddGigasecond(t time.Time) time.Time {
+	return t.Add(1000000000 * time.Second)
+}

go/gigasecond/gigasecond_test.go

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+package gigasecond
+
+// Write a function AddGigasecond that works with time.Time.
+
+import (
+	"os"
+	"testing"
+	"time"
+)
+
+// date formats used in test data
+const (
+	fmtD  = "2006-01-02"
+	fmtDT = "2006-01-02T15:04:05"
+)
+
+func TestAddGigasecond(t *testing.T) {
+	for _, tc := range addCases {
+		in := parse(tc.in, t)
+		want := parse(tc.want, t)
+		got := AddGigasecond(in)
+		if !got.Equal(want) {
+			t.Fatalf(`FAIL: %s
+AddGigasecond(%s)
+   = %s
+want %s`, tc.description, in, got, want)
+		}
+		t.Log("PASS:", tc.description)
+	}
+	t.Log("Tested", len(addCases), "cases.")
+}
+
+func parse(s string, t *testing.T) time.Time {
+	tt, err := time.Parse(fmtDT, s) // try full date time format first
+	if err != nil {
+		tt, err = time.Parse(fmtD, s) // also allow just date
+	}
+	if err != nil {
+		// can't run tests if input won't parse.  if this seems to be a
+		// development or ci environment, raise an error.  if this condition
+		// makes it to the solver though, ask for a bug report.
+		_, statErr := os.Stat("example_gen.go")
+		if statErr == nil || os.Getenv("TRAVIS_GO_VERSION") > "" {
+			t.Fatal(err)
+		} else {
+			t.Log(err)
+			t.Skip("(This is not your fault, and is unexpected.  " +
+				"Please file an issue at https://github.com/exercism/go.)")
+		}
+	}
+	return tt
+}
+
+func BenchmarkAddGigasecond(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		AddGigasecond(time.Time{})
+	}
+}