Leave empty files out of report and trees (closes #178) (#183)

internal/sfdupes/report_test.go

@@ -434,6 +434,27 @@ func TestDupeGroups(t *testing.T) {
 	}
 }
 
+// TestDupeGroupsLeavesOutEmptyFiles checks that empty files form no
+// duplicate group, while 1-byte files still do.
+func TestDupeGroupsLeavesOutEmptyFiles(t *testing.T) {
+	t.Parallel()
+
+	e, x := sha256.Sum256(nil), testHash("x")
+	recs := []scanRec{
+		{size: 0, head: e, tail: e, content: e, path: "/a/.gitkeep"},
+		{size: 0, head: e, tail: e, content: e, path: "/b/.gitkeep"},
+		{size: 0, head: e, tail: e, content: e, path: "/c/__init__.py"},
+		{size: 1, head: x, tail: x, content: x, path: "/tiny1"},
+		{size: 1, head: x, tail: x, content: x, path: "/tiny2"},
+	}
+
+	groups := dupeGroupsOf(t, recs)
+	if len(groups) != 1 || groups[0].size != 1 ||
+		!slices.Equal(groups[0].paths, []string{"/tiny1", "/tiny2"}) {
+		t.Fatalf("groups = %+v, want only /tiny1 /tiny2 of size 1", groups)
+	}
+}
+
 func TestDupeGroupsContentSeparates(t *testing.T) {
 	t.Parallel()