test(getFirstBitPosition): Add test

applet/src/test/java/tests/BigNatInternal/getFirstBitPositionTest.java

@@ -0,0 +1,87 @@
+package tests.BigNatInternal;
+
+import javacard.framework.JCSystem;
+import opencrypto.jcmathlib.BigNat;
+import opencrypto.jcmathlib.ResourceManager;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class getFirstBitPositionTest {
+    @Test
+    public void noZero() {
+        ResourceManager rm = new ResourceManager((short) 256);
+        byte memoryType = JCSystem.MEMORY_TYPE_TRANSIENT_RESET;
+        BigNat bn = new BigNat((short) 10, memoryType, rm);
+
+        byte[] data = {(byte) 0xff};
+        bn.fromByteArray(data, (short) 0, (short) data.length);
+
+        short position = bn.getFirstBitPosition((byte) 0);
+        Assertions.assertEquals((short) 8, position); /* no zero bit */
+    }
+
+    @Test
+    public void noOne() {
+        ResourceManager rm = new ResourceManager((short) 256);
+        byte memoryType = JCSystem.MEMORY_TYPE_TRANSIENT_RESET;
+        BigNat bn = new BigNat((short) 10, memoryType, rm);
+
+        byte[] data = {(byte) 0x00};
+        bn.fromByteArray(data, (short) 0, (short) data.length);
+
+        short position = bn.getFirstBitPosition((byte) 1);
+        Assertions.assertEquals((short) 8, position); /* no zero bit */
+    }
+
+    @Test
+    public void oneByteZero() {
+        ResourceManager rm = new ResourceManager((short) 256);
+        byte memoryType = JCSystem.MEMORY_TYPE_TRANSIENT_RESET;
+        BigNat bn = new BigNat((short) 3, memoryType, rm);
+
+        byte[] data = {(byte) 0x1f};
+        bn.fromByteArray(data, (short) 0, (short) data.length);
+
+        short position = bn.getFirstBitPosition((byte) 0);
+        Assertions.assertEquals((short) 5, position);
+    }
+
+    @Test
+    public void oneByteOne() {
+        ResourceManager rm = new ResourceManager((short) 256);
+        byte memoryType = JCSystem.MEMORY_TYPE_TRANSIENT_RESET;
+        BigNat bn = new BigNat((short) 3, memoryType, rm);
+
+        byte[] data = {(byte) 0x20};
+        bn.fromByteArray(data, (short) 0, (short) data.length);
+
+        short position = bn.getFirstBitPosition((byte) 1);
+        Assertions.assertEquals((short) 5, position);
+    }
+
+    @Test
+    public void twoBytesZero() {
+        ResourceManager rm = new ResourceManager((short) 256);
+        byte memoryType = JCSystem.MEMORY_TYPE_TRANSIENT_RESET;
+        BigNat bn = new BigNat((short) 3, memoryType, rm);
+
+        byte[] data = {(byte) 0x3F, (byte) 0xff};
+        bn.fromByteArray(data, (short) 0, (short) data.length);
+
+        short position = bn.getFirstBitPosition((byte) 0);
+        Assertions.assertEquals((short) 14, position);
+    }
+
+    @Test
+    public void twoBytesOne() {
+        ResourceManager rm = new ResourceManager((short) 256);
+        byte memoryType = JCSystem.MEMORY_TYPE_TRANSIENT_RESET;
+        BigNat bn = new BigNat((short) 3, memoryType, rm);
+
+        byte[] data = {(byte) 0xC0, (byte) 0x00};
+        bn.fromByteArray(data, (short) 0, (short) data.length);
+
+        short position = bn.getFirstBitPosition((byte) 1);
+        Assertions.assertEquals((short) 14, position);
+    }
+}