refactor: cleanup code

Author: nanmu42

block.go

@@ -7,7 +7,10 @@
 
 package etherscan
 
-import "strconv"
+import (
+	"fmt"
+	"strconv"
+)
 
 // BlockReward gets block and uncle rewards by block number
 func (c *Client) BlockReward(blockNum int) (rewards BlockRewards, err error) {
@@ -19,21 +22,28 @@ func (c *Client) BlockReward(blockNum int) (rewards BlockRewards, err error) {
 	return
 }
 
-// BlockNumber gets closest block number by UNIX timestamp
+// BlockNumber gets the closest block number by UNIX timestamp
+//
+// valid closest option: before, after
 func (c *Client) BlockNumber(timestamp int64, closest string) (blockNumber int, err error) {
-	var result string
+	var blockNumberStr string
+
 	param := M{
-		"timestamp": strconv.Itoa(int(timestamp)),
+		"timestamp": strconv.FormatInt(timestamp, 10),
 		"closest":   closest,
 	}
 
-	err = c.call("block", "getblocknobytime", param, &result)
+	err = c.call("block", "getblocknobytime", param, &blockNumberStr)
+
+	if err != nil {
+		return
+	}
 
+	blockNumber, err = strconv.Atoi(blockNumberStr)
 	if err != nil {
+		err = fmt.Errorf("parsing block number %q: %w", blockNumberStr, err)
 		return
 	}
 
-	blockNum, err := strconv.ParseInt(result, 10, 64)
-	blockNumber = int(blockNum)
 	return
 }

block_e2e_test.go

@@ -26,21 +26,21 @@ func TestClient_BlockReward(t *testing.T) {
 }
 
 func TestClient_BlockNumber(t *testing.T) {
-	//Note: All values taken from docs.etherscan.io/api-endpoints/blocks
-	const ans_before = 9251482
-	const ans_after = 9251483
+	// Note: All values taken from docs.etherscan.io/api-endpoints/blocks
+	const ansBefore = 9251482
+	const ansAfter = 9251483
 
 	blockNumber, err := api.BlockNumber(1578638524, "before")
 	noError(t, err, "api.BlockNumber")
 
-	if blockNumber != ans_before {
-		t.Errorf(`api.BlockNumber(1578638524, "before") not working, got %d, want %d`, blockNumber, ans_before)
+	if blockNumber != ansBefore {
+		t.Errorf(`api.BlockNumber(1578638524, "before") not working, got %d, want %d`, blockNumber, ansBefore)
 	}
 
 	blockNumber, err = api.BlockNumber(1578638524, "after")
 	noError(t, err, "api.BlockNumber")
 
-	if blockNumber != ans_after {
-		t.Errorf(`api.BlockNumber(1578638524,"after") not working, got %d, want %d`, blockNumber, ans_after)
+	if blockNumber != ansAfter {
+		t.Errorf(`api.BlockNumber(1578638524,"after") not working, got %d, want %d`, blockNumber, ansAfter)
 	}
 }