Add more tests, fix array when input is aligned

multiplatform-crypto-libsodium-bindings/src/commonTest/kotlin/com/ionspin/kotlin/crypto/util/LibsodiumUtilTest.kt

@@ -24,4 +24,32 @@ class LibsodiumUtilTest {
             input.contentEquals(unpadded)
         }
     }
+
+    @Test
+    fun testPaddingAligned() {
+        val input = ubyteArrayOf(1U, 2U)
+        val blocksize = 2
+        val padded = LibsodiumUtil.pad(input, blocksize)
+        println(padded.hexColumsPrint())
+        val unpadded = LibsodiumUtil.unpad(padded, blocksize)
+        println(unpadded.hexColumsPrint())
+
+        assertTrue {
+            input.contentEquals(unpadded)
+        }
+    }
+
+    @Test
+    fun testPaddingMultiblock() {
+        val input = ubyteArrayOf(1U, 2U, 3U, 4U, 5U, 6U)
+        val blocksize = 4
+        val padded = LibsodiumUtil.pad(input, blocksize)
+        println(padded.hexColumsPrint())
+        val unpadded = LibsodiumUtil.unpad(padded, blocksize)
+        println(unpadded.hexColumsPrint())
+
+        assertTrue {
+            input.contentEquals(unpadded)
+        }
+    }
 }

multiplatform-crypto-libsodium-bindings/src/nativeMain/kotlin/com/ionspin/kotlin/crypto/util/LibsodiumUtil.kt

@@ -37,7 +37,7 @@ actual object LibsodiumUtil {
         val resultingSize = if (unpaddedData.size % blocksize != 0 ) {
             ((unpaddedData.size / blocksize) + 1 ) * blocksize
         } else {
-            unpaddedData.size + 1
+            unpaddedData.size
         }
         val paddedData = UByteArray(resultingSize)
         unpaddedData.copyInto(paddedData, 0, 0)