Add very basic "oci-platform" string test

Author: tianon

architecture/oci-platform_test.go

@@ -0,0 +1,23 @@
+package architecture_test
+
+import (
+	"testing"
+
+	"github.com/docker-library/bashbrew/architecture"
+)
+
+func TestString(t *testing.T) {
+	tests := map[string]string{
+		"amd64":         "linux/amd64",
+		"arm32v6":       "linux/arm/v6",
+		"windows-amd64": "windows/amd64",
+	}
+	for arch, platform := range tests {
+		t.Run(arch, func(t *testing.T) {
+			oci := architecture.SupportedArches[arch]
+			if ociPlatform := oci.String(); platform != ociPlatform {
+				t.Errorf("expected %q; got %q", platform, ociPlatform)
+			}
+		})
+	}
+}