Warn about duplicate files when syncing - fixes #1506

Error about unsorted directories and test thoroughly

fs/sync_internal_test.go

@@ -0,0 +1,129 @@
+// Internal tests for sync/copy/move
+
+package fs
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMatchListings(t *testing.T) {
+	var (
+		a = mockObject("a")
+		b = mockObject("b")
+		c = mockObject("c")
+		d = mockObject("d")
+	)
+
+	for _, test := range []struct {
+		what    string
+		input   DirEntries // pairs of input src, dst
+		srcOnly DirEntries
+		dstOnly DirEntries
+		matches []matchPair // pairs of output
+	}{
+		{
+			what: "only src or dst",
+			input: DirEntries{
+				a, nil,
+				b, nil,
+				c, nil,
+				d, nil,
+			},
+			srcOnly: DirEntries{
+				a, b, c, d,
+			},
+		},
+		{
+			what: "typical sync #1",
+			input: DirEntries{
+				a, nil,
+				b, b,
+				nil, c,
+				nil, d,
+			},
+			srcOnly: DirEntries{
+				a,
+			},
+			dstOnly: DirEntries{
+				c, d,
+			},
+			matches: []matchPair{
+				{b, b},
+			},
+		},
+		{
+			what: "typical sync #2",
+			input: DirEntries{
+				a, a,
+				b, b,
+				nil, c,
+				d, d,
+			},
+			dstOnly: DirEntries{
+				c,
+			},
+			matches: []matchPair{
+				{a, a},
+				{b, b},
+				{d, d},
+			},
+		},
+		{
+			what: "One duplicate",
+			input: DirEntries{
+				a, a,
+				a, nil,
+			},
+			matches: []matchPair{
+				{a, a},
+			},
+		},
+		{
+			what: "Two duplicates",
+			input: DirEntries{
+				a, a,
+				a, a,
+				a, nil,
+			},
+			matches: []matchPair{
+				{a, a},
+			},
+		},
+		{
+			what: "Out of order",
+			input: DirEntries{
+				c, nil,
+				b, b,
+				a, nil,
+			},
+			srcOnly: DirEntries{
+				c,
+			},
+			dstOnly: DirEntries{
+				b,
+			},
+		},
+	} {
+		var srcList, dstList DirEntries
+		for i := 0; i < len(test.input); i += 2 {
+			src, dst := test.input[i], test.input[i+1]
+			if src != nil {
+				srcList = append(srcList, src)
+			}
+			if dst != nil {
+				dstList = append(dstList, dst)
+			}
+		}
+		srcOnly, dstOnly, matches := matchListings(srcList, dstList)
+		assert.Equal(t, test.srcOnly, srcOnly, test.what)
+		assert.Equal(t, test.dstOnly, dstOnly, test.what)
+		assert.Equal(t, test.matches, matches, test.what)
+		// now swap src and dst
+		dstOnly, srcOnly, matches = matchListings(dstList, srcList)
+		assert.Equal(t, test.srcOnly, srcOnly, test.what)
+		assert.Equal(t, test.dstOnly, dstOnly, test.what)
+		assert.Equal(t, test.matches, matches, test.what)
+	}
+}