tests: [zstd] Unit tests for sequenceDecs.adjustOffset (#525)

zstd/seqdec_test.go

@@ -0,0 +1,119 @@
+package zstd
+
+import (
+	"testing"
+)
+
+func TestSequenceDecsAdjustOffset(t *testing.T) {
+	type result struct {
+		offset     int
+		prevOffset [3]int
+	}
+
+	tc := []struct {
+		offset     int
+		litLen     int
+		offsetB    uint8
+		prevOffset [3]int
+
+		res result
+	}{{
+		offset:     444,
+		litLen:     0,
+		offsetB:    42,
+		prevOffset: [3]int{111, 222, 333},
+
+		res: result{
+			offset:     444,
+			prevOffset: [3]int{444, 111, 222},
+		},
+	}, {
+		offset:     0,
+		litLen:     1,
+		offsetB:    0,
+		prevOffset: [3]int{111, 222, 333},
+
+		res: result{
+			offset:     111,
+			prevOffset: [3]int{111, 222, 333},
+		},
+	}, {
+		offset:     -1,
+		litLen:     0,
+		offsetB:    0,
+		prevOffset: [3]int{111, 222, 333},
+
+		res: result{
+			offset:     111,
+			prevOffset: [3]int{111, 222, 333},
+		},
+	}, {
+		offset:     1,
+		litLen:     1,
+		offsetB:    0,
+		prevOffset: [3]int{111, 222, 333},
+
+		res: result{
+			offset:     222,
+			prevOffset: [3]int{222, 111, 333},
+		},
+	}, {
+		offset:     2,
+		litLen:     1,
+		offsetB:    0,
+		prevOffset: [3]int{111, 222, 333},
+
+		res: result{
+			offset:     333,
+			prevOffset: [3]int{333, 111, 222},
+		},
+	}, {
+		offset:     3,
+		litLen:     1,
+		offsetB:    0,
+		prevOffset: [3]int{111, 222, 333},
+
+		res: result{
+			offset:     110, // s.prevOffset[0] - 1
+			prevOffset: [3]int{110, 111, 222},
+		},
+	}, {
+		offset:     3,
+		litLen:     1,
+		offsetB:    0,
+		prevOffset: [3]int{1, 222, 333},
+
+		res: result{
+			offset:     1,
+			prevOffset: [3]int{1, 1, 222},
+		},
+	},
+	}
+
+	for i := range tc {
+		// given
+		var sd sequenceDecs
+		for j := 0; j < 3; j++ {
+			sd.prevOffset[j] = tc[i].prevOffset[j]
+		}
+
+		// when
+		offset := sd.adjustOffset(tc[i].offset, tc[i].litLen, tc[i].offsetB)
+
+		// then
+		if offset != tc[i].res.offset {
+			t.Logf("result:   %d", offset)
+			t.Logf("expected: %d", tc[i].res.offset)
+			t.Errorf("testcase #%d: wrong function result", i)
+		}
+
+		for j := 0; j < 3; j++ {
+			if sd.prevOffset[j] != tc[i].res.prevOffset[j] {
+				t.Logf("result:   %v", sd.prevOffset)
+				t.Logf("expected: %v", tc[i].res.prevOffset)
+				t.Errorf("testcase #%d: sd.prevOffset got wrongly updated", i)
+				break
+			}
+		}
+	}
+}