1 files changed, 122 insertions, 0 deletions
diff --git a/compressor/compressor_test.go b/compressor/compressor_test.go
new file mode 100644
index 0000000..621b731
--- /dev/null
+++ b/compressor/compressor_test.go
@@ -0,0 +1,122 @@
+package compressor
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestCompressor_Compress(t *testing.T) {
+	x := 0 // an empty value
+
+	allCompressors := func() []Compressor {
+		return []Compressor{
+			NewUniqueEntriesTable(),
+			NewRowDisplacementTable(x),
+		}
+	}
+
+	tests := []struct {
+		original    []int
+		rowCount    int
+		colCount    int
+		compressors []Compressor
+	}{
+		{
+			original: []int{
+				1, 1, 1, 1, 1,
+				1, 1, 1, 1, 1,
+				1, 1, 1, 1, 1,
+			},
+			rowCount:    3,
+			colCount:    5,
+			compressors: allCompressors(),
+		},
+		{
+			original: []int{
+				x, x, x, x, x,
+				x, x, x, x, x,
+				x, x, x, x, x,
+			},
+			rowCount:    3,
+			colCount:    5,
+			compressors: allCompressors(),
+		},
+		{
+			original: []int{
+				1, 1, 1, 1, 1,
+				x, x, x, x, x,
+				1, 1, 1, 1, 1,
+			},
+			rowCount:    3,
+			colCount:    5,
+			compressors: allCompressors(),
+		},
+		{
+			original: []int{
+				1, x, 1, 1, 1,
+				1, 1, x, 1, 1,
+				1, 1, 1, x, 1,
+			},
+			rowCount:    3,
+			colCount:    5,
+			compressors: allCompressors(),
+		},
+	}
+	for i, tt := range tests {
+		for _, comp := range tt.compressors {
+			t.Run(fmt.Sprintf("%T #%v", comp, i), func(t *testing.T) {
+				dup := make([]int, len(tt.original))
+				copy(dup, tt.original)
+
+				orig, err := NewOriginalTable(tt.original, tt.colCount)
+				if err != nil {
+					t.Fatal(err)
+				}
+				err = comp.Compress(orig)
+				if err != nil {
+					t.Fatal(err)
+				}
+				rowCount, colCount := comp.OriginalTableSize()
+				if rowCount != tt.rowCount || colCount != tt.colCount {
+					t.Fatalf("unexpected table size; want: %vx%v, got: %vx%v", tt.rowCount, tt.colCount, rowCount, colCount)
+				}
+				for i := 0; i < tt.rowCount; i++ {
+					for j := 0; j < tt.colCount; j++ {
+						v, err := comp.Lookup(i, j)
+						if err != nil {
+							t.Fatal(err)
+						}
+						expected := tt.original[i*tt.colCount+j]
+						if v != expected {
+							t.Fatalf("unexpected entry (%v, %v); want: %v, got: %v", i, j, expected, v)
+						}
+					}
+				}
+
+				// Calling with out-of-range indexes should be an error.
+				if _, err := comp.Lookup(0, -1); err == nil {
+					t.Fatalf("expected error didn't occur (0, -1)")
+				}
+				if _, err := comp.Lookup(-1, 0); err == nil {
+					t.Fatalf("expected error didn't occur (-1, 0)")
+				}
+				if _, err := comp.Lookup(rowCount-1, colCount); err == nil {
+					t.Fatalf("expected error didn't occur (%v, %v)", rowCount-1, colCount)
+				}
+				if _, err := comp.Lookup(rowCount, colCount-1); err == nil {
+					t.Fatalf("expected error didn't occur (%v, %v)", rowCount, colCount-1)
+				}
+
+				// The compressor must not break the original table.
+				for i := 0; i < tt.rowCount; i++ {
+					for j := 0; j < tt.colCount; j++ {
+						idx := i*tt.colCount + j
+						if tt.original[idx] != dup[idx] {
+							t.Fatalf("the original table is broken (%v, %v); want: %v, got: %v", i, j, dup[idx], tt.original[idx])
+						}
+					}
+				}
+			})
+		}
+	}
+}