stop being a jerk and add the context string to test_vectors.json

c/test.py

@@ -8,7 +8,6 @@
 HERE = path.dirname(__file__)
 TEST_VECTORS_PATH = path.join(HERE, "..", "test_vectors", "test_vectors.json")
 TEST_VECTORS = json.load(open(TEST_VECTORS_PATH))
-TEST_CONTEXT = "BLAKE3 2019-12-27 16:29:52 test vectors context"
 
 
 def run_blake3(args, input):
@@ -37,6 +36,7 @@ def main():
         input_len = case["input_len"]
         input = make_test_input(input_len)
         hex_key = hexlify(TEST_VECTORS["key"].encode())
+        context_string = TEST_VECTORS["context_string"]
         expected_hash_xof = case["hash"]
         expected_hash = expected_hash_xof[:64]
         expected_keyed_hash_xof = case["keyed_hash"]
@@ -76,7 +76,7 @@ def main():
                     input_len, expected_keyed_hash_xof, line)
 
         # Test the default derive key.
-        test_derive_key = run_blake3(["--derive-key", TEST_CONTEXT], input)
+        test_derive_key = run_blake3(["--derive-key", context_string], input)
         for line in test_derive_key.splitlines():
             assert expected_derive_key == line, \
                 "derive_key({}): {} != {}".format(
@@ -85,7 +85,7 @@ def main():
         # Test the extended derive key.
         xof_len = len(expected_derive_key_xof) // 2
         test_derive_key_xof = run_blake3(
-            ["--derive-key", TEST_CONTEXT, "--length",
+            ["--derive-key", context_string, "--length",
              str(xof_len)], input)
         for line in test_derive_key_xof.splitlines():
             assert expected_derive_key_xof == line, \

test_vectors/src/lib.rs

@@ -30,20 +30,19 @@ pub const TEST_CASES: &[usize] = &[
     100 * CHUNK_LEN, // subtrees larger than MAX_SIMD_DEGREE chunks
 ];
 
+pub const TEST_KEY: &[u8; blake3::KEY_LEN] = b"whats the Elvish word for friend";
 pub const TEST_CONTEXT: &str = "BLAKE3 2019-12-27 16:29:52 test vectors context";
 
 const COMMENT: &str = r#"
 Each test is an input length and three outputs, one for each of the hash,
 keyed_hash, and derive_key modes. The input in each case is filled with a
-251-byte-long repeating pattern: 0, 1, 2, ..., 249, 250, 0, 1, ... The key used
-with keyed_hash is the 32-byte ASCII string given in the 'key' field below. For
-derive_key, the test input is used as the input key, and the context string is
-'BLAKE3 2019-12-27 16:29:52 test vectors context'. (As good practice for
-following the security requirements of derive_key, test runners should make
-that context string a hardcoded constant, and we do not provided it in
-machine-readable form.) Outputs are encoded as hexadecimal. Each case is an
-extended output, and implementations should also check that the first 32 bytes
-match their default-length output.
+repeating sequence of 251 bytes: 0, 1, 2, ..., 249, 250, 0, 1, ..., and so on.
+The key used with keyed_hash is the 32-byte ASCII string "whats the Elvish word
+for friend", also given in the `key` field below. The context string used with
+derive_key is the ASCII string "BLAKE3 2019-12-27 16:29:52 test vectors
+context", also given in the `context_string` field below. Outputs are encoded
+as hexadecimal. Each case is an extended output, and implementations should
+also check that the first 32 bytes match their default-length output.
 "#;
 
 // Paint the input with a repeating byte pattern. We use a cycle length of 251,
@@ -60,6 +59,7 @@ pub fn paint_test_input(buf: &mut [u8]) {
 pub struct Cases {
     pub _comment: String,
     pub key: String,
+    pub context_string: String,
     pub cases: Vec<Case>,
 }
 
@@ -72,8 +72,6 @@ pub struct Case {
 }
 
 pub fn generate_json() -> String {
-    const TEST_KEY: &[u8; blake3::KEY_LEN] = b"whats the Elvish word for friend";
-
     let mut cases = Vec::new();
     for &input_len in TEST_CASES {
         let mut input = vec![0; input_len];
@@ -108,6 +106,7 @@ pub fn generate_json() -> String {
     let mut json = serde_json::to_string_pretty(&Cases {
         _comment: COMMENT.trim().replace("\n", " "),
         key: std::str::from_utf8(TEST_KEY).unwrap().to_string(),
+        context_string: TEST_CONTEXT.to_string(),
         cases,
     })
     .unwrap();

test_vectors/test_vectors.json

@@ -1,6 +1,7 @@
 {
-  "_comment": "Each test is an input length and three outputs, one for each of the hash, keyed_hash, and derive_key modes. The input in each case is filled with a 251-byte-long repeating pattern: 0, 1, 2, ..., 249, 250, 0, 1, ... The key used with keyed_hash is the 32-byte ASCII string given in the 'key' field below. For derive_key, the test input is used as the input key, and the context string is 'BLAKE3 2019-12-27 16:29:52 test vectors context'. (As good practice for following the security requirements of derive_key, test runners should make that context string a hardcoded constant, and we do not provided it in machine-readable form.) Outputs are encoded as hexadecimal. Each case is an extended output, and implementations should also check that the first 32 bytes match their default-length output.",
+  "_comment": "Each test is an input length and three outputs, one for each of the hash, keyed_hash, and derive_key modes. The input in each case is filled with a repeating sequence of 251 bytes: 0, 1, 2, ..., 249, 250, 0, 1, ..., and so on. The key used with keyed_hash is the 32-byte ASCII string \"whats the Elvish word for friend\", also given in the `key` field below. The context string used with derive_key is the ASCII string \"BLAKE3 2019-12-27 16:29:52 test vectors context\", also given in the `context_string` field below. Outputs are encoded as hexadecimal. Each case is an extended output, and implementations should also check that the first 32 bytes match their default-length output.",
   "key": "whats the Elvish word for friend",
+  "context_string": "BLAKE3 2019-12-27 16:29:52 test vectors context",
   "cases": [
     {
       "input_len": 0,