diff --git a/tests/test_flatten.cpp b/tests/test_flatten.cpp
index 534c3dd0d..f19b89b00 100644
--- a/tests/test_flatten.cpp
+++ b/tests/test_flatten.cpp
@@ -66,18 +66,18 @@ static int test_flatten_int8(const ncnn::Mat& a)
 static int test_flatten_1()
 {
     return 0
-           || test_flatten_int8(RandomS8Mat(2, 4, 4))
-           || test_flatten_int8(RandomS8Mat(3, 5, 8))
-           || test_flatten_int8(RandomS8Mat(1, 1, 16))
-           || test_flatten_int8(RandomS8Mat(9, 10, 16))
-           || test_flatten_int8(RandomS8Mat(1, 7, 1))
-           || test_flatten_int8(RandomS8Mat(6, 6, 15))
-           || test_flatten_int8(RandomS8Mat(13, 13))
-           || test_flatten_int8(RandomS8Mat(16, 16))
-           || test_flatten_int8(RandomS8Mat(8, 12))
-           || test_flatten_int8(RandomS8Mat(8, 2))
-           || test_flatten_int8(RandomS8Mat(32))
-           || test_flatten_int8(RandomS8Mat(17));
+           || test_flatten_int8(RandomS8Mat(2, 4, 16))
+           || test_flatten_int8(RandomS8Mat(3, 5, 32))
+           || test_flatten_int8(RandomS8Mat(1, 1, 64))
+           || test_flatten_int8(RandomS8Mat(9, 10, 64))
+           || test_flatten_int8(RandomS8Mat(1, 7, 4))
+           || test_flatten_int8(RandomS8Mat(6, 6, 70))
+           || test_flatten_int8(RandomS8Mat(13, 52))
+           || test_flatten_int8(RandomS8Mat(16, 64))
+           || test_flatten_int8(RandomS8Mat(8, 48))
+           || test_flatten_int8(RandomS8Mat(8, 8))
+           || test_flatten_int8(RandomS8Mat(128))
+           || test_flatten_int8(RandomS8Mat(127));
 }
 
 int main()
diff --git a/tests/test_padding.cpp b/tests/test_padding.cpp
index 504dea64b..c0e9fd1f2 100644
--- a/tests/test_padding.cpp
+++ b/tests/test_padding.cpp
@@ -217,9 +217,9 @@ static int test_padding_int8(const ncnn::Mat& a, int top, int bottom, int left,
 
 static int test_padding_3()
 {
-    ncnn::Mat a = RandomS8Mat(9, 11, 24);
-    ncnn::Mat b = RandomS8Mat(10, 13, 12);
-    ncnn::Mat c = RandomS8Mat(8, 9, 13);
+    ncnn::Mat a = RandomS8Mat(9, 11, 96);
+    ncnn::Mat b = RandomS8Mat(10, 13, 48);
+    ncnn::Mat c = RandomS8Mat(8, 9, 52);
 
     return 0
            || test_padding_int8(a, 0, 0, 0, 0, 0, 0, 0, 0.f, 0)
@@ -277,9 +277,9 @@ static int test_padding_3()
 
 static int test_padding_4()
 {
-    ncnn::Mat a = RandomS8Mat(15, 24);
-    ncnn::Mat b = RandomS8Mat(19, 12);
-    ncnn::Mat c = RandomS8Mat(17, 15);
+    ncnn::Mat a = RandomS8Mat(15, 96);
+    ncnn::Mat b = RandomS8Mat(19, 48);
+    ncnn::Mat c = RandomS8Mat(17, 60);
 
     return 0
            || test_padding_int8(a, 0, 0, 0, 0, 0, 0, 0, 0.f, 0)