tests/test-sparse-clone.t

rust-cpython: prepare for writing tests that require libpython

What I wanted is to disable the "cpython/extension-module<ver>" feature
while building tests executable, but that seems not doable. Instead,
this patch adds new features dedicated for tests.

The make rule is extracted so that we can easily run cargo tests.

Added a minimal test of ref-sharing as an example. More tests will follow.

test sparse

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > ssh = "$PYTHON" "$RUNTESTDIR/dummyssh"
  > username = nobody <[e-mail]>
  > [extensions]
  > sparse=
  > purge=
  > strip=
  > rebase=
  > EOF

  $ hg init myrepo
  $ cd myrepo
  $ echo a > index.html
  $ echo x > data.py
  $ echo z > readme.txt
  $ cat > webpage.sparse <<EOF
  > [include]
  > *.html
  > EOF
  $ cat > backend.sparse <<EOF
  > [include]
  > *.py
  > EOF
  $ hg ci -Aqm 'initial'
  $ cd ..

Verify local clone with a sparse profile works

  $ hg clone --enable-profile webpage.sparse myrepo clone1
  updating to branch default
  warning: sparse profile 'webpage.sparse' not found in rev 000000000000 - ignoring it
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clone1
  $ ls
  index.html
  $ cd ..

Verify local clone with include works

  $ hg clone --include *.sparse myrepo clone2
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clone2
  $ ls
  backend.sparse
  webpage.sparse
  $ cd ..

Verify local clone with exclude works

  $ hg clone --exclude data.py myrepo clone3
  updating to branch default
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clone3
  $ ls
  backend.sparse
  index.html
  readme.txt
  webpage.sparse
  $ cd ..

Verify sparse clone profile over ssh works

  $ hg clone -q --enable-profile webpage.sparse ssh://user@dummy/myrepo clone4
  warning: sparse profile 'webpage.sparse' not found in rev 000000000000 - ignoring it
  $ cd clone4
  $ ls
  index.html
  $ cd ..