Add tests for CFI round-tripping

src/pyj/read_book/cfi.pyj

@@ -136,7 +136,9 @@ def encode(doc, node, offset, tail):  # {{{
     # Handle the offset, if any
     if node.nodeType is Node.ELEMENT_NODE:
         if jstype(offset) is 'number':
-            node = node.childNodes.item(offset)
+            q = node.childNodes.item(offset)
+            if q and q.nodeType is Node.ELEMENT_NODE:
+                node = q
     elif Node.TEXT_NODE <= node.nodeType <= Node.ENTITY_NODE:
         offset = offset or 0
         while True:
@@ -212,7 +214,7 @@ def decode(cfi, doc): # {{{
                     cfi = cfi.substr(r[0].length)
                     break
                 index |= 1 # Increment index by 1 if it is even
-                if child.nodeType is 1:
+                if child.nodeType is Node.ELEMENT_NODE:
                     index += 1
                 if index is target:
                     cfi = cfi.substr(r[0].length)
@@ -276,8 +278,6 @@ def decode(cfi, doc): # {{{
             # TODO: Handle text assertion
 
     # Find the text node that contains the offset
-    if node and node.parentNode:
-        node.parentNode.normalize()
     if offset is not None:
         while True:
             l = node.nodeValue.length

src/pyj/read_book/test_cfi.pyj

@@ -2,11 +2,46 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 from __python__ import bound_methods, hash_literals
 
-from read_book.cfi import escape_for_cfi, unescape_from_cfi
-from testing import test, assert_equal
+from elementmaker import E
+
+from read_book.cfi import encode, decode, escape_for_cfi, unescape_from_cfi
+from testing import assert_equal, test
 
 
 @test
 def cfi_escaping():
     t = 'a^!,1'
     assert_equal(t, unescape_from_cfi(escape_for_cfi(t)))
+
+
+@test
+def cfi_roundtripping():
+    idc = 0
+    def nid():
+        nonlocal idc
+        idc += 1
+        return idc + ''
+
+    document.body.appendChild(E.p('abc'))
+    p = document.body.firstChild
+    path_to_p = '/2/4/2'
+    assert_equal(encode(document, p), path_to_p)
+    assert_equal(decode(path_to_p), {'node': p})
+
+    assert_equal(encode(document, p.firstChild), f'{path_to_p}/1:0')
+    assert_equal(decode(f'{path_to_p}/1:0'), {'node': p.firstChild, 'offset': 0})
+
+    assert_equal(encode(document, p.firstChild, 1), f'{path_to_p}/1:1')
+    assert_equal(decode(f'{path_to_p}/1:1'), {'node': p.firstChild, 'offset': 1})
+
+    p.appendChild(document.createTextNode('def'))
+    assert_equal(encode(document, p.firstChild, 5), f'{path_to_p}/1:5')
+    assert_equal(p.childNodes.length, 2)
+    assert_equal(encode(document, p.lastChild, 1), f'{path_to_p}/1:4')
+    assert_equal(decode(f'{path_to_p}/1:5'), {'node': p.lastChild, 'offset': 2})
+    assert_equal(decode(f'{path_to_p}/1:1'), {'node': p.firstChild, 'offset': 1})
+
+    p.appendChild(E.span('123', id=nid()))
+    p.appendChild(document.createTextNode('456'))
+    assert_equal(encode(document, p.lastChild, 1), f'{path_to_p}/1:7')
+    assert_equal(decode(f'{path_to_p}/1:7'), {'node': p.lastChild, 'offset': 1})

src/pyj/test.pyj

@@ -25,8 +25,8 @@ def get_traceback(lines):
     lines = traceback.format_exception()
     last_line = lines[-1]
     final_lines = v'[]'
-    pat = /at assert_\w+ \(/
-    for line in lines:
+    pat = /at assert_[0-9a-zA-Z_]+ \(/
+    for line in lines[:-1]:
         if pat.test(line):
             break
         final_lines.push(line)

src/pyj/testing.pyj

@@ -14,10 +14,21 @@ def raise_fail(preamble, msg, call_site):
     raise AssertionError(preamble + msg)
 
 
+def repr_of(a):
+    if not a:
+        return a
+    q = a.outerHTML
+    if q:
+        return q.split('>')[0] + '>'
+    return a
+
+
 def assert_equal(a, b, msg, call_site=None):
 
     def fail():
-        p = f'{a} != {b}'
+        ra = repr_of(a)
+        rb = repr_of(b)
+        p = f'{ra} != {rb}'
         raise_fail(p, msg, call_site)
 
     atype = jstype(a)
@@ -31,10 +42,18 @@ def assert_equal(a, b, msg, call_site=None):
         if not a.__eq__(b):
             fail()
         return
+    if a.isSameNode:
+        if not a.isSameNode(b):
+            fail()
+        return
     if b.__eq__:
         if not b.__eq__(a):
             fail()
         return
+    if b.isSameNode:
+        if not b.isSameNode(a):
+            fail()
+        return
     if a.length? or b.length?:
         if a.length is not b.length:
             fail()
@@ -48,7 +67,7 @@ def assert_equal(a, b, msg, call_site=None):
         for key in Object.keys(b):
             assert_equal(a[key], b[key])
 
-    if a is not b:
+    if atype is not 'object' and btype is not 'object':
         fail()