WIP: draft incomplete keep rule for keeping most recent common ancestor

pruning/keep_most_recent_common_ancestor_test.go

@@ -0,0 +1,31 @@
+package pruning
+
+import "testing"
+
+func TestKeppMostRecentCommonAncestor(t *testing.T) {
+
+	o := func(minutes int) time.Time {
+		return time.Unix(123, 0).Add(time.Duration(minutes) * time.Minute)
+	}
+
+	tcs := map[string]testCase{
+		"empty": {
+			inputs:     []Snapshot{},
+			rules:      []KeepRule{NewKeepMostRecentCommonAncestor()},
+			expDestroy: map[string]bool{},
+		},
+		"nil": {
+			inputs:     nil,
+			rules:      []KeepRule{NewKeepMostRecentCommonAncestor()},
+			expDestroy: map[string]bool{},
+		},
+		"": {
+			inputs: []Snapshot{
+				stubSnap{name: "s1", date: o(5), bothSides: }
+			},
+		}
+	}
+
+	testTable(tcs, t)
+
+}