1 files changed, 107 insertions, 0 deletions
diff --git a/src/test/model/asn1/TagTest.java b/src/test/model/asn1/TagTest.java
new file mode 100644
index 0000000..02df91f
--- /dev/null
+++ b/src/test/model/asn1/TagTest.java
@@ -0,0 +1,107 @@
+package model.asn1;
+
+import model.asn1.exceptions.ParseException;
+import model.asn1.parsing.BytesReader;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class TagTest {
+    @Test
+    void testConstructor() {
+        assertEquals(ASN1Object.TAG_SEQUENCE.getNumber(),
+                new Tag(TagClass.UNIVERSAL, false, ASN1Object.TAG_SEQUENCE.getNumber()).getNumber());
+        assertEquals(ASN1Object.TAG_SEQUENCE.getCls(),
+                new Tag(TagClass.UNIVERSAL, false, ASN1Object.TAG_SEQUENCE.getNumber()).getCls());
+        assertEquals(ASN1Object.TAG_SEQUENCE.isConstructive(),
+                new Tag(TagClass.UNIVERSAL,
+                        ASN1Object.TAG_SEQUENCE.isConstructive(),
+                        ASN1Object.TAG_SEQUENCE.getNumber())
+                        .isConstructive());
+    }
+
+    @Test
+    void testParseSuccess() throws ParseException {
+        // Test basic parsing
+        assertEquals(0x1,
+                new Tag(new BytesReader(new Byte[]{ 0x1 })).getNumber());
+        assertEquals(TagClass.UNIVERSAL,
+                new Tag(new BytesReader(new Byte[]{ 0x1 })).getCls());
+        assertFalse(new Tag(new BytesReader(new Byte[]{ 0x1 })).isConstructive());
+        // Test basic parsing with different class
+        assertEquals(5,
+                new Tag(new BytesReader(new Byte[]{ 101 })).getNumber());
+        assertEquals(TagClass.APPLICATION,
+                new Tag(new BytesReader(new Byte[]{ 101 })).getCls());
+        assertTrue(new Tag(new BytesReader(new Byte[]{ 101 })).isConstructive());
+        // Test different classes
+        assertEquals(TagClass.UNIVERSAL,
+                new Tag(new BytesReader(new Byte[]{ 1 })).getCls()); // 0b00000001
+        assertEquals(TagClass.PRIVATE,
+                new Tag(new BytesReader(new Byte[]{ -63 })).getCls()); // 0b11000001
+        assertEquals(TagClass.CONTEXT_SPECIFIC,
+                new Tag(new BytesReader(new Byte[]{ -127 })).getCls()); // 0b10000001
+        assertEquals(TagClass.APPLICATION,
+                new Tag(new BytesReader(new Byte[]{ 65 })).getCls()); // 0b01000001
+        // Test different numbers
+        assertEquals(0x10,
+                new Tag(new BytesReader(new Byte[]{ 0x10 })).getNumber());
+        assertEquals(31,
+                new Tag(new BytesReader(new Byte[]{ 31 })).getNumber());
+        // Test constructive bit
+        assertFalse(new Tag(new BytesReader(new Byte[]{ 0x1 })).isConstructive());
+        assertTrue(new Tag(new BytesReader(new Byte[]{ 33 })).isConstructive());
+        // Test modification
+        BytesReader reader = new BytesReader(new Byte[]{ 33 });
+        assertEquals(0, reader.getIndex());
+        new Tag(reader);
+        assertEquals(1, reader.getIndex());
+    }
+
+    @Test
+    void testParseFail() {
+        // No enough bytes
+        assertThrows(ParseException.class, () -> {
+            BytesReader reader = new BytesReader(new Byte[]{ 33 });
+            reader.require(1, true);
+            new Tag(reader);
+        });
+        // Number zero
+        assertThrows(ParseException.class, () -> new Tag(new BytesReader(new Byte[]{ 0 })));
+    }
+
+    @Test
+    void testEncode() {
+        // Basic encoding
+        assertArrayEquals(new Byte[]{ 1 }, new Tag(TagClass.UNIVERSAL, false, 1).encodeDER());
+        assertArrayEquals(new Byte[]{ 31 }, new Tag(TagClass.UNIVERSAL, false, 31).encodeDER());
+        // With different class
+        assertArrayEquals(new Byte[]{ -127 }, new Tag(TagClass.CONTEXT_SPECIFIC, false, 1).encodeDER());
+        assertArrayEquals(new Byte[]{ -61 }, new Tag(TagClass.PRIVATE, false, 3).encodeDER());
+        assertArrayEquals(new Byte[]{ 71 }, new Tag(TagClass.APPLICATION, false, 7).encodeDER());
+        // With different constructive bit
+        assertArrayEquals(new Byte[]{ 63 }, new Tag(TagClass.UNIVERSAL, true, 31).encodeDER());
+    }
+
+    @Test
+    void testEnforce() {
+        assertThrows(ParseException.class, () ->
+                new Tag(TagClass.UNIVERSAL, true, 10)
+                        .enforce(new Tag(TagClass.UNIVERSAL, true, 9)));
+        assertThrows(ParseException.class, () ->
+                new Tag(TagClass.UNIVERSAL, true, 10)
+                        .enforce(new Tag(TagClass.UNIVERSAL, true, 11)));
+        assertThrows(ParseException.class, () ->
+                new Tag(TagClass.UNIVERSAL, true, 10)
+                        .enforce(new Tag(TagClass.UNIVERSAL, false, 10)));
+        assertThrows(ParseException.class, () ->
+                new Tag(TagClass.UNIVERSAL, true, 10)
+                        .enforce(new Tag(TagClass.APPLICATION, true, 10)));
+        assertThrows(ParseException.class, () ->
+                new Tag(TagClass.UNIVERSAL, true, 10)
+                        .enforce(new Tag(TagClass.PRIVATE, true, 10)));
+        assertThrows(ParseException.class, () ->
+                new Tag(TagClass.UNIVERSAL, true, 10)
+                        .enforce(new Tag(TagClass.CONTEXT_SPECIFIC, true, 10)));
+    }
+}