Add HTTP header deletion, improve tests

lib/pure/httpcore.nim

@@ -154,6 +154,10 @@ proc add*(headers: HttpHeaders, key, value: string) =
   else:
     headers.table[key.toLowerAscii].add(value)
 
+proc del*(headers: HttpHeaders, key: string) =
+  ## Delete the header entries associated with ``key``
+  headers.table.del(key.toLowerAscii)
+
 iterator pairs*(headers: HttpHeaders): tuple[key, value: string] =
   ## Yields each key, value pair.
   for k, v in headers.table:

tests/stdlib/thttpcore.nim

@@ -0,0 +1,28 @@
+
+import unittest
+
+import httpcore
+
+suite "httpcore":
+
+  test "HttpCode":
+    assert $Http418 == "418 I'm a teapot"
+    assert Http418.is4xx() == true
+    assert Http418.is2xx() == false
+
+  test "headers":
+    var h = newHttpHeaders()
+    assert h.len == 0
+    h.add("Cookie", "foo")
+    assert h.len == 1
+    assert h.hasKey("cooKIE")
+    assert h["Cookie"] == "foo"
+    assert h["cookie"] == "foo"
+    h["cookie"] = @["bar", "x"]
+    assert h["Cookie"] == "bar"
+    assert h["Cookie", 1] == "x"
+    assert h["Cookie"].contains("BaR") == true
+    assert h["Cookie"].contains("X") == true
+    assert "baR" in h["cookiE"]
+    h.del("coOKie")
+    assert h.len == 0