tests/test-bdiff.py

extensions: move the "import" logic out from "load"

The "load" method does too many things: on-demand import and check version.
This patch moves the import logic out from "load" so it could be wrapped to
change the import behavior, for example, chg will use it to pre-import
extensions.

from __future__ import absolute_import, print_function
import struct
from mercurial import (
    bdiff,
    mpatch,
)

def test1(a, b):
    d = bdiff.bdiff(a, b)
    c = a
    if d:
        c = mpatch.patches(a, [d])
    if c != b:
        print("***", repr(a), repr(b))
        print("bad:")
        print(repr(c)[:200])
        print(repr(d))

def test(a, b):
    print("***", repr(a), repr(b))
    test1(a, b)
    test1(b, a)

test("a\nc\n\n\n\n", "a\nb\n\n\n")
test("a\nb\nc\n", "a\nc\n")
test("", "")
test("a\nb\nc", "a\nb\nc")
test("a\nb\nc\nd\n", "a\nd\n")
test("a\nb\nc\nd\n", "a\nc\ne\n")
test("a\nb\nc\n", "a\nc\n")
test("a\n", "c\na\nb\n")
test("a\n", "")
test("a\n", "b\nc\n")
test("a\n", "c\na\n")
test("", "adjfkjdjksdhfksj")
test("", "ab")
test("", "abc")
test("a", "a")
test("ab", "ab")
test("abc", "abc")
test("a\n", "a\n")
test("a\nb", "a\nb")

#issue1295
def showdiff(a, b):
    bin = bdiff.bdiff(a, b)
    pos = 0
    while pos < len(bin):
        p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
        pos += 12
        print(p1, p2, repr(bin[pos:pos + l]))
        pos += l
showdiff("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\nx\n\nz\n")
showdiff("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n")
# we should pick up abbbc. rather than bc.de as the longest match
showdiff("a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
         "a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n")

print("done")

def testfixws(a, b, allws):
    c = bdiff.fixws(a, allws)
    if c != b:
        print("*** fixws", repr(a), repr(b), allws)
        print("got:")
        print(repr(c))

testfixws(" \ta\r b\t\n", "ab\n", 1)
testfixws(" \ta\r b\t\n", " a b\n", 0)
testfixws("", "", 1)
testfixws("", "", 0)

print("done")