live: add testcase

Signed-off-by: jsvisa <delweng@gmail.com>

eth/tracers/live/filter_api_test.go

@@ -0,0 +1,89 @@
+package live
+
+import (
+	"testing"
+)
+
+func testGen(blknum uint64) ([]interface{}, error) {
+	traces := make([]interface{}, 5)
+	for i := range traces {
+		traces[i] = int(blknum*5) + i
+	}
+	return traces, nil
+}
+
+func TestExportLimitedTraces(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name      string
+		fromBlock uint64
+		toBlock   uint64
+		count     uint64
+		after     uint64
+		want      []int
+	}{
+		{
+			name:      "Basic Test",
+			fromBlock: 0,
+			toBlock:   2,
+			count:     10,
+			after:     0,
+			want: []int{
+				0, 1, 2, 3, 4, // the first block
+				5, 6, 7, 8, 9, // the second block
+			},
+		},
+		{
+			name:      "With After",
+			fromBlock: 0,
+			toBlock:   0,
+			count:     3,
+			after:     2,
+			want: []int{
+				2,    // the first block left
+				3, 4, // the second block
+			},
+		},
+		{
+			name:      "With After",
+			fromBlock: 0,
+			toBlock:   0,
+			count:     3,
+			after:     2,
+			want: []int{
+				2,    // the first block left
+				3, 4, // the second block
+			},
+		},
+
+		{
+			name:      "Not Enough Traces",
+			fromBlock: 0,
+			toBlock:   0,
+			count:     10,
+			after:     5,
+			want:      nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			have, err := exportLimitedTraces(testGen, tt.fromBlock, tt.toBlock, tt.count, tt.after)
+			if err != nil {
+				t.Error(err)
+				return
+			}
+
+			if hl, wl := len(have), len(tt.want); hl != wl {
+				t.Errorf("test(%s) exported len not equal, have %d, want %d", tt.name, hl, wl)
+				return
+			}
+			for i := range have {
+				if h, w := have[i].(int), tt.want[i]; h != w {
+					t.Errorf("test(%s) result not equal have %v want %v at index %d", tt.name, h, w, i)
+				}
+			}
+		})
+	}
+}