unikernel/duniverse/dune_/test/blackbox-tests/test-cases/print-diff.t

@@ -0,0 +1,137 @@
+  $ cat > dune-project << EOF
+  > (lang dune 3.0)
+  > EOF
+
+  $ cat > dune << EOF
+  > (rule
+  >  (alias runtest)
+  >  (action
+  >   (diff a b)))
+  > 
+  > (rule (write-file b b))
+  > EOF
+
+  $ cat > a << EOF
+  > a
+  > EOF
+
+--diff-command accepts a command name that is passed both files.
+
+  $ dune runtest --diff-command echo
+  a b
+  File "a", line 1, characters 0-0:
+  Error: command reported no differences: cd _build/default && echo a b
+  [1]
+
+If the command succeeds (reports no diff), this is displayed.
+
+  $ dune runtest --diff-command true
+  File "a", line 1, characters 0-0:
+  Error: command reported no differences: cd _build/default && true a b
+  [1]
+
+If the command fails, this is displayed too.
+
+  $ dune runtest --diff-command false
+  File "a", line 1, characters 0-0:
+  Command exited with code 1.
+  [1]
+
+As a special case, - can be passed and just the fact that they differ is
+printed.
+
+  $ dune runtest --diff-command -
+  File "a", line 1, characters 0-0:
+  Error: Files _build/default/a and _build/default/b differ.
+  [1]
+
+The default behavior (when --diff-command is not passed) is equivalent to
+`--diff-cmd` when testing dune.
+
+  $ dune runtest
+  File "a", line 1, characters 0-0:
+  Error: Files _build/default/a and _build/default/b differ.
+  [1]
+
+Outside of dune, it is to first look for patdiff in PATH.
+
+To simulate what happens inside of dune, we'll need to setup a _path directory
+with just the required binaries. _tools contains succeed (that prints its
+arguments and succeeds) and fail (that prints its arguments and fails). In
+addition to unsetting INSIDE_DUNE, we also need to pass
+--always-show-command-line in order to have the same results locally and in CI.
+
+  $ mkdir _tools
+  $ cat > _tools/succeed << 'EOF'
+  > #!/bin/sh
+  > echo Running "$0" "$@"
+  > EOF
+  $ chmod +x _tools/succeed
+  $ cat > _tools/fail << 'EOF'
+  > #!/bin/sh
+  > echo Running "$0" "$@"
+  > false
+  > EOF
+  $ chmod +x _tools/fail
+  $ mkdir _path
+  $ ln -s $(command -v dune) _path/
+  $ ln -s $(command -v ocamlc) _path/
+
+  $ cp _tools/fail _path/patdiff
+  $ cp _tools/fail _path/diff
+  $ cp _tools/fail _path/git
+
+  $ (unset INSIDE_DUNE; PATH=_path dune runtest --always-show-command-line --root .)
+  File "a", line 1, characters 0-0:
+  (cd _build/default && $TESTCASE_ROOT/_path/patdiff -keep-whitespace -location-style omake -ascii a b)
+  Running $TESTCASE_ROOT/_path/patdiff -keep-whitespace -location-style omake -ascii a b
+  [1]
+
+Otherwise, it will use git diff.
+
+  $ rm _path/patdiff
+  $ (unset INSIDE_DUNE; PATH=_path dune runtest --always-show-command-line --root .)
+  File "a", line 1, characters 0-0:
+  $TESTCASE_ROOT/_path/git --no-pager diff --no-index --color=always -u _build/default/a _build/default/b
+  Running $TESTCASE_ROOT/_path/git --no-pager diff --no-index --color=always -u _build/default/a _build/default/b
+  [1]
+
+This also happens if patdiff returns no difference.
+
+  $ cp _tools/succeed _path/patdiff
+  $ (unset INSIDE_DUNE; PATH=_path dune runtest --always-show-command-line --root .)
+  (cd _build/default && $TESTCASE_ROOT/_path/patdiff -keep-whitespace -location-style omake -ascii a b)
+  Running $TESTCASE_ROOT/_path/patdiff -keep-whitespace -location-style omake -ascii a b
+  File "a", line 1, characters 0-0:
+  $TESTCASE_ROOT/_path/git --no-pager diff --no-index --color=always -u _build/default/a _build/default/b
+  Running $TESTCASE_ROOT/_path/git --no-pager diff --no-index --color=always -u _build/default/a _build/default/b
+  [1]
+
+If patdiff or git are unavailable, it uses diff.
+
+  $ rm _path/patdiff
+  $ rm _path/git
+  $ (unset INSIDE_DUNE; PATH=_path dune runtest --always-show-command-line --root .)
+  File "a", line 1, characters 0-0:
+  (cd _build/default && $TESTCASE_ROOT/_path/diff -u a b)
+  Running $TESTCASE_ROOT/_path/diff -u a b
+  [1]
+
+In this situation (when an automatically discovered command is used), if the
+command succeeds, the "difference" message is still printed.
+
+  $ cp _tools/succeed _path/diff
+  $ (unset INSIDE_DUNE; PATH=_path dune runtest --always-show-command-line --root .)
+  (cd _build/default && $TESTCASE_ROOT/_path/diff -u a b)
+  Running $TESTCASE_ROOT/_path/diff -u a b
+  File "a", line 1, characters 0-0:
+  Error: Files _build/default/a and _build/default/b differ.
+  [1]
+
+If diff is also not available, it just reports a difference.
+
+  $ rm _path/diff
+  $ (unset INSIDE_DUNE; PATH=_path dune runtest --always-show-command-line --root .)
+  File "a", line 1, characters 0-0:
+  Error: Files _build/default/a and _build/default/b differ.
+  [1]