sgf-parsing: Add individual tests of escaping/whitespace behaviour

11c36323-93fc-495d-bb23-c88ee5844b8c crams too much into one test case.
Split it up into multiple ones.

In addition, 11c36323-93fc-495d-bb23-c88ee5844b8c has behaviour that
violates the specification. The violation is that `\t` and `\n` (written
as `"\\t"` and `"\\n"` in the JSON string, respectively), do not hold
any sort of special significance in SGF, according to the specification:
https://www.red-bean.com/sgf/sgf4.html

Reimplement in 08e4b8ba-bb07-4431-a3d9-b1f4cdea6dab.

The reimplemented case is mostly as it was when the exercise was
originally implemented in
exercism/exercism@7a5075b
and the reimplemented case is in accordance with the specification.

Note that the original case also got it wrong in that newlines should
remain newlines; this is corrected in
08e4b8ba-bb07-4431-a3d9-b1f4cdea6dab.

Author: petertseng

exercises/sgf-parsing/canonical-data.json

@@ -170,6 +170,171 @@
                 "children": []
             }
         },
+        {
+            "uuid": "28092c06-275f-4b9f-a6be-95663e69d4db",
+            "description": "within property values, whitespace characters such as tab are converted to spaces",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[hello\t\tworld])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["hello  world"]
+                },
+                "children": []
+            }
+        },
+        {
+            "uuid": "deaecb9d-b6df-4658-aa92-dcd70f4d472a",
+            "description": "within property values, newlines remain as newlines",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[hello\n\nworld])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["hello\n\nworld"]
+                },
+                "children": []
+            }
+        },
+        {
+            "uuid": "8e4c970e-42d7-440e-bfef-5d7a296868ef",
+            "description": "Escaped closing bracket in property value is inserted verbatim",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[\\]])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["]"]
+                },
+                "children": []
+            }
+        },
+        {
+            "uuid": "cf371fa8-ba4a-45ec-82fb-38668edcb15f",
+            "description": "Escaped backslash in property value is inserted verbatim",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[\\\\])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["\\"]
+                },
+                "children": []
+            }
+        },
+        {
+            "uuid": "dc13ca67-fac0-4b65-b3fe-c584d6a2c523",
+            "description": "Opening bracket in property value doesn't need to be escaped",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[x[y\\]z]B[foo];C[bar])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["x[y]z"],
+                    "B": ["foo"]
+                },
+                "children": [
+                    {
+                        "properties": {
+                            "C": ["bar"]
+                        },
+                        "children": []
+                    }
+                ]
+            }
+        },
+        {
+            "uuid": "a780b97e-8dbb-474e-8f7e-4031902190e8",
+            "description": "Semicolon in property value doesn't need to be escaped",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[a;b]B[foo];C[bar])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["a;b"],
+                    "B": ["foo"]
+                },
+                "children": [
+                    {
+                        "properties": {
+                            "C": ["bar"]
+                        },
+                        "children": []
+                    }
+                ]
+            }
+        },
+        {
+            "uuid": "0b57a79e-8d89-49e5-82b6-2eaaa6b88ed7",
+            "description": "Parentheses in property value don't need to be escaped",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[x(y)z]B[foo];C[bar])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["x(y)z"],
+                    "B": ["foo"]
+                },
+                "children": [
+                    {
+                        "properties": {
+                            "C": ["bar"]
+                        },
+                        "children": []
+                    }
+                ]
+            }
+        },
+        {
+            "uuid": "3a1023d2-7484-4498-8d73-3666bb386e81",
+            "description": "Escaped newline is in property value converted to nothing at all",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[hello\\\nworld])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["helloworld"]
+                },
+                "children": []
+            }
+        },
+        {
+            "uuid": "25abf1a4-5205-46f1-8c72-53273b94d009",
+            "description": "Escaped t and n in property value are just letters, not whitespace",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[\\t = t and \\n = n])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["t = t and n = n"]
+                },
+                "children": []
+            }
+        },
+        {
+            "uuid": "08e4b8ba-bb07-4431-a3d9-b1f4cdea6dab",
+            "reimplements": "11c36323-93fc-495d-bb23-c88ee5844b8c",
+            "description": "mixing various kinds of whitespace and escaped characters in property value",
+            "property": "parse",
+            "input": {
+                "encoded": "(;A[\\]b\nc\\\nd\t\te\\\\ \\\n\\]])"
+            },
+            "expected": {
+                "properties": {
+                    "A": ["]b\ncd  e\\ ]"]
+                },
+                "children": []
+            }
+        },
         {
             "uuid": "11c36323-93fc-495d-bb23-c88ee5844b8c",
             "description": "escaped property",