From 3e3454552f7c7b1122eb9318fee7e8407aade044 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Tue, 26 Apr 2022 14:22:12 +0100
Subject: [PATCH] parser tests

---
 tests/test_parser.py | 56 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 tests/test_parser.py

diff --git a/tests/test_parser.py b/tests/test_parser.py
new file mode 100644
index 000000000..f77e86d18
--- /dev/null
+++ b/tests/test_parser.py
@@ -0,0 +1,56 @@
+from textual._parser import Parser
+
+
+def test_read1():
+    class TestParser(Parser[str]):
+        """A simple parser that reads a byte at a time from a stream."""
+
+        def parse(self, on_token):
+            while True:
+                data = yield self.read1()
+                if not data:
+                    break
+                on_token(data)
+
+    test_parser = TestParser()
+
+    test_data = "Where there is a Will there is a way!"
+
+    for size in range(1, len(test_data) + 1):
+        # Feed the parser in pieces, first 1 character at a time, then 2, etc
+        test_parser = TestParser()
+        data = []
+        for offset in range(0, len(test_data), size):
+            for chunk in test_parser.feed(test_data[offset : offset + size]):
+                data.append(chunk)
+        # Check we have received all the data in characters, no matter the fee dsize
+        assert len(data) == len(test_data)
+        assert "".join(data) == test_data
+
+
+def test_read():
+    class TestParser(Parser[str]):
+        """A parser that reads chunks of a given size from the stream."""
+
+        def __init__(self, size):
+            self.size = size
+            super().__init__()
+
+        def parse(self, on_token):
+            while True:
+                data = yield self.read1()
+                if not data:
+                    break
+                on_token(data)
+
+    test_data = "Where there is a Will there is a way!"
+
+    for read_size in range(1, len(test_data) + 1):
+        test_parser = TestParser(read_size)
+        for size in range(1, len(test_data) + 1):
+            test_parser = TestParser(read_size)
+            data = []
+            for offset in range(0, len(test_data), size):
+                for chunk in test_parser.feed(test_data[offset : offset + size]):
+                    data.append(chunk)
+            assert "".join(data) == test_data