test: verify sentinel + decode-error conformance vectors

Harness + CI now check sentinel.jsonl and errors.jsonl at vectors v1.1.0.

Author: ajsb85

.github/workflows/ci.yml

@@ -49,8 +49,14 @@ jobs:
       - name: Install SDK packages
         run: sdkmanager "platforms;android-35" "build-tools;36.0.0"
       - name: Download shared conformance vectors
-        run: curl -sSfL -o vectors.jsonl https://raw.githubusercontent.com/firechip/cobs-conformance/v1.0.0/vectors/vectors.jsonl
+        run: |
+          base=https://raw.githubusercontent.com/firechip/cobs-conformance/v1.1.0/vectors
+          curl -sSfL -o vectors.jsonl "$base/vectors.jsonl"
+          curl -sSfL -o sentinel.jsonl "$base/sentinel.jsonl"
+          curl -sSfL -o errors.jsonl "$base/errors.jsonl"
       - name: Check conformance
         env:
           COBS_CONFORMANCE_VECTORS: ${{ github.workspace }}/vectors.jsonl
+          COBS_CONFORMANCE_SENTINEL: ${{ github.workspace }}/sentinel.jsonl
+          COBS_CONFORMANCE_ERRORS: ${{ github.workspace }}/errors.jsonl
         run: ./gradlew :cobs:testDebugUnitTest --tests "dev.firechip.cobs.ConformanceTest" --console=plain

cobs/src/test/kotlin/dev/firechip/cobs/ConformanceTest.kt

@@ -5,16 +5,21 @@ package dev.firechip.cobs
 
 import java.io.File
 import org.junit.Assert.assertArrayEquals
+import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
+import org.junit.Assert.fail
 import org.junit.Assume.assumeTrue
 import org.junit.Test
 
 /**
  * Verifies this library against the shared conformance vectors from
  * https://github.com/firechip/cobs-conformance
  *
- * Skipped unless the `COBS_CONFORMANCE_VECTORS` environment variable points to a
- * downloaded `vectors.jsonl` (CI sets this; local `./gradlew test` skips it).
+ * Each check is skipped unless the corresponding environment variable points to a
+ * downloaded JSONL file (CI sets these; local `./gradlew test` skips them):
+ *  - `COBS_CONFORMANCE_VECTORS`  -> `vectors.jsonl`  {decoded, cobs, cobsr}
+ *  - `COBS_CONFORMANCE_SENTINEL` -> `sentinel.jsonl` {decoded, sentinel, cobs, cobsr}
+ *  - `COBS_CONFORMANCE_ERRORS`   -> `errors.jsonl`   {encoded, cobs, cobsr}
  */
 class ConformanceTest {
 
@@ -52,4 +57,78 @@ class ConformanceTest {
         }
         assertTrue("no vectors checked", count > 0)
     }
+
+    @Test
+    fun conformsToSentinelVectors() {
+        val path = System.getenv("COBS_CONFORMANCE_SENTINEL")
+        assumeTrue("set COBS_CONFORMANCE_SENTINEL to run", !path.isNullOrBlank())
+
+        val regex = Regex(
+            "\"decoded\":\"([0-9a-f]*)\",\"sentinel\":\"([0-9a-f]*)\"," +
+                "\"cobs\":\"([0-9a-f]*)\",\"cobsr\":\"([0-9a-f]*)\"",
+        )
+        var count = 0
+        File(path!!).forEachLine { line ->
+            if (line.isBlank()) return@forEachLine
+            val match = regex.find(line) ?: error("malformed sentinel line: $line")
+            val (d, s, c, cr) = match.destructured
+            val data = hex(d)
+            val sentinel = hex(s)[0]
+            val cobs = hex(c)
+            val cobsr = hex(cr)
+            assertArrayEquals("cobs sentinel $s encode $d", cobs, Cobs.encodeWithSentinel(data, sentinel))
+            assertArrayEquals("cobsr sentinel $s encode $d", cobsr, Cobsr.encodeWithSentinel(data, sentinel))
+            assertArrayEquals("cobs sentinel $s decode $c", data, Cobs.decodeWithSentinel(cobs, sentinel))
+            assertArrayEquals("cobsr sentinel $s decode $cr", data, Cobsr.decodeWithSentinel(cobsr, sentinel))
+            assertFalse("sentinel $s must not appear in cobs $c", cobs.contains(sentinel))
+            assertFalse("sentinel $s must not appear in cobsr $cr", cobsr.contains(sentinel))
+            count++
+        }
+        assertTrue("no sentinel vectors checked", count > 0)
+    }
+
+    @Test
+    fun conformsToErrorVectors() {
+        val path = System.getenv("COBS_CONFORMANCE_ERRORS")
+        assumeTrue("set COBS_CONFORMANCE_ERRORS to run", !path.isNullOrBlank())
+
+        val regex = Regex(
+            "\"encoded\":\"([0-9a-f]*)\",\"cobs\":(null|\"[0-9a-f]*\")," +
+                "\"cobsr\":(null|\"[0-9a-f]*\")",
+        )
+        var count = 0
+        File(path!!).forEachLine { line ->
+            if (line.isBlank()) return@forEachLine
+            val match = regex.find(line) ?: error("malformed error line: $line")
+            val (e, c, cr) = match.destructured
+            val encoded = hex(e)
+            checkDecode("cobs decode $e", c, encoded) { Cobs.decode(it) }
+            checkDecode("cobsr decode $e", cr, encoded) { Cobsr.decode(it) }
+            count++
+        }
+        assertTrue("no error vectors checked", count > 0)
+    }
+
+    /**
+     * Asserts that [decode] applied to [encoded] either fails (when [field] is the
+     * JSON literal `null`) or produces the hex payload quoted in [field].
+     */
+    private fun checkDecode(
+        label: String,
+        field: String,
+        encoded: ByteArray,
+        decode: (ByteArray) -> ByteArray,
+    ) {
+        if (field == "null") {
+            try {
+                decode(encoded)
+                fail("$label: expected decode to fail but it succeeded")
+            } catch (_: CobsDecodeException) {
+                // expected: this input MUST fail to decode
+            }
+        } else {
+            val expected = hex(field.substring(1, field.length - 1))
+            assertArrayEquals(label, expected, decode(encoded))
+        }
+    }
 }