fix: update test coverage

Author: lxlxw

Diff for: solution/1-99/0001.two-sum/solution_test.go

@@ -10,7 +10,6 @@ func TestTwoSum(t *testing.T) {
 	nums := []int{1, 2, 3}
 	target := 3
 	result := []int{0, 1}
-
 	fmt.Printf("nums = %v target = %v result = %v\n", nums, target, twoSum(nums, target))
 	if ret := twoSum(nums, target); ret[0] != result[0] && ret[1] != result[1] {
 		t.Fatalf("case fails: %v\n", ret)
@@ -19,9 +18,15 @@ func TestTwoSum(t *testing.T) {
 	nums = []int{1, 10, 20, 30}
 	target = 30
 	result = []int{1, 2}
-
 	fmt.Printf("nums = %v target = %v result = %v\n", nums, target, twoSum(nums, target))
 	if ret := twoSum(nums, target); ret[0] != result[0] && ret[1] != result[1] {
 		t.Fatalf("case fails: %v\n", ret)
 	}
+
+	nums = []int{}
+	target = 0
+	fmt.Printf("nums = %v target = %v result = %v\n", nums, target, twoSum(nums, target))
+	if ret := twoSum(nums, target); len(ret) != 0 {
+		t.Fatalf("case fails: %v\n", ret)
+	}
 }

Diff for: solution/1-99/0009.palindrome-number/solution_test.go

@@ -10,6 +10,12 @@ func TestIsPalindrome(t *testing.T) {
 	var x int
 	var ret bool = true
 
+	x = -1
+	fmt.Printf("x = %v ret = %v\n", x, isPalindrome(x))
+	if isPalindrome(x) == ret {
+		t.Fatalf("case fails: %v\n", ret)
+	}
+
 	x = 121
 	fmt.Printf("x = %v ret = %v\n", x, isPalindrome(x))
 	if isPalindrome(x) != ret {

Diff for: solution/1-99/0026.remove-duplicates-from-sorted-array/solution_test.go

@@ -18,4 +18,10 @@ func TestRemoveDuplicates(t *testing.T) {
 	if removeDuplicates(nums2) != ret {
 		t.Fatalf("case fails: %v\n", ret)
 	}
+
+	nums3 := []int{}
+	ret = 0
+	if removeDuplicates(nums3) != ret {
+		t.Fatalf("case fails: %v\n", ret)
+	}
 }