implement tests

also fix MD5

src/commonTest/kotlin/com/infendro/hash/sha2/SHA-224.kt

@@ -0,0 +1,33 @@
+package com.infendro.hash.sha2
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+
+class `SHA-224 Test` {
+    val function = `SHA-224`
+
+    @Test
+    fun `bytes and block`() {
+        assertEquals(28, function.bytes)
+        assertEquals(224, function.bits)
+        assertEquals(64, function.block)
+    }
+
+    @Test
+    fun `empty bytearray`() {
+        val expected = ubyteArrayOf(
+            0xd1U, 0x4aU, 0x02U, 0x8cU,
+            0x2aU, 0x3aU, 0x2bU, 0xc9U,
+            0x47U, 0x61U, 0x02U, 0xbbU,
+            0x28U, 0x82U, 0x34U, 0xc4U,
+            0x15U, 0xa2U, 0xb0U, 0x1fU,
+            0x82U, 0x8eU, 0xa6U, 0x2aU,
+            0xc5U, 0xb3U, 0xe4U, 0x2fU,
+        )
+        val actual = function.hash(
+            ubyteArrayOf()
+        )
+        assertContentEquals(expected, actual)
+    }
+}