Add CI tests for ARM64

.travis.yml

@@ -1,13 +1,17 @@
 language: go
-dist: xenial
-go:
-  - 1.12.x
-  - 1.13.x
+arch:
+  - amd64
+  - arm64
+dist: focal
+go: 1.15.x
 script:
   - diff -u <(echo -n) <(gofmt -d *.go)
   - diff -u <(echo -n) <(golint $(go list -e ./...) | grep -v YAMLToJSON)
   - GO111MODULE=on go vet .
   - GO111MODULE=on go test -v -race ./...
+  - if [[ $TRAVIS_CPU_ARCH == "arm64" ]]; then
+      GOARCH=arm GOARM=7 GO111MODULE=on go test -v ./...;
+    fi
   - git diff --exit-code
 install:
   - GO111MODULE=off go get golang.org/x/lint/golint

yaml_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"math"
 	"reflect"
+	"runtime"
 	"sort"
 	"strconv"
 	"testing"
@@ -22,6 +23,9 @@ type MarshalTest struct {
 }
 
 func TestMarshal(t *testing.T) {
+	if runtime.GOARCH == "arm" {
+		t.Skip("constant 9223372036854775807 overflows int")
+	}
 	f32String := strconv.FormatFloat(math.MaxFloat32, 'g', -1, 32)
 	s := MarshalTest{"a", math.MaxInt64, math.MaxFloat32}
 	e := []byte(fmt.Sprintf("A: a\nB: %d\nC: %s\n", math.MaxInt64, f32String))