keyword: unify keyword synonyms

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

hierarchy_test.go

@@ -0,0 +1,38 @@
+package mtree
+
+import (
+	"strings"
+	"testing"
+)
+
+var checklist = []struct {
+	blob string
+	set  []string
+}{
+	{blob: `
+#       machine: bananaboat
+#          tree: .git
+#          date: Wed Nov 16 14:54:17 2016
+
+# .
+/set type=file nlink=1 mode=0664 uid=1000 gid=100
+. size=4096 type=dir mode=0755 nlink=8 time=1479326055.423853146
+  .COMMIT_EDITMSG.un~ size=1006 mode=0644 time=1479325423.450468662 sha1digest=dead0face
+  .TAG_EDITMSG.un~ size=1069 mode=0600 time=1471362316.801317529 sha256digest=dead0face
+`, set: []string{"size", "mode", "time", "sha256digest"}},
+}
+
+func TestUsedKeywords(t *testing.T) {
+	for i, item := range checklist {
+		dh, err := ParseSpec(strings.NewReader(item.blob))
+		if err != nil {
+			t.Error(err)
+		}
+		used := dh.UsedKeywords()
+		for _, k := range item.set {
+			if !inSlice(k, used) {
+				t.Errorf("%d: expected to find %q in %q", i, k, used)
+			}
+		}
+	}
+}