bundlespec: fix the "streamv2" and "streamv3-exp" variant

In c4aab3661f25, we broken this feature by adding unicode instead of bytes to
the dictionary.

On the other hand, this feature was never tested, so augment the tests to tests
this.

mercurial/bundlecaches.py

@@ -136,7 +136,7 b' class bundlespec:'
         b'cg.version': b'02',
         b'obsolescence': False,
         b'phases': False,
-        b"stream": "v2",
+        b"stream": b"v2",
         b'tagsfnodescache': False,
         b'revbranchcache': False,
     },
@@ -145,7 +145,7 b' class bundlespec:'
         b'cg.version': b'03',
         b'obsolescence': False,
         b'phases': False,
-        b"stream": "v3-exp",
+        b"stream": b"v3-exp",
         b'tagsfnodescache': False,
         b'revbranchcache': False,
     },

tests/test-stream-bundle-v2.t

@@ -74,6 +74,23 b' The extension requires a repo (currently'
   none-v2;stream=v3-exp;requirements%3Dgeneraldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog (stream-v3 zstd no-rust !)
   none-v2;stream=v3-exp;requirements%3Dgeneraldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog (stream-v3 rust !)
 
+  $ hg bundle -a --type="none-$bundle_format" bundle.hg
+  $ hg debugbundle bundle.hg
+  Stream params: {}
+  stream2 -- {bytecount: 1693, filecount: 12, requirements: generaldelta%2Crevlogv1%2Csparserevlog} (mandatory: True) (stream-v2 no-zstd !)
+  stream2 -- {bytecount: 1693, filecount: 12, requirements: generaldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog} (mandatory: True) (stream-v2 zstd no-rust !)
+  stream2 -- {bytecount: 1819, filecount: 14, requirements: generaldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog} (mandatory: True) (stream-v2 rust !)
+  stream3-exp -- {requirements: generaldelta%2Crevlogv1%2Csparserevlog} (mandatory: True) (stream-v3 no-zstd !)
+  stream3-exp -- {requirements: generaldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog} (mandatory: True) (stream-v3 zstd no-rust !)
+  stream3-exp -- {requirements: generaldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog} (mandatory: True) (stream-v3 rust !)
+  $ hg debugbundle --spec bundle.hg
+  none-v2;stream=v2;requirements%3Dgeneraldelta%2Crevlogv1%2Csparserevlog (stream-v2 no-zstd !)
+  none-v2;stream=v2;requirements%3Dgeneraldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog (stream-v2 zstd no-rust !)
+  none-v2;stream=v2;requirements%3Dgeneraldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog (stream-v2 rust !)
+  none-v2;stream=v3-exp;requirements%3Dgeneraldelta%2Crevlogv1%2Csparserevlog (stream-v3 no-zstd !)
+  none-v2;stream=v3-exp;requirements%3Dgeneraldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog (stream-v3 zstd no-rust !)
+  none-v2;stream=v3-exp;requirements%3Dgeneraldelta%2Crevlog-compression-zstd%2Crevlogv1%2Csparserevlog (stream-v3 rust !)
+
 Test that we can apply the bundle as a stream clone bundle
 
   $ cat > .hg/clonebundles.manifest << EOF