reftest: add more test cases for W59

* Shows the difference of behaviour between 'opam lint' and 'opam lint --check-upstream'
* Add test cases for special cases: conf flag, url containing git url

master_changes.md

@@ -187,6 +187,7 @@ users)
   * lint: add E71 test [#5561 @rjbou]
   * lint: add E72 test [#5561 @rjbou]
   * lint: add E73 test [#5561 @rjbou]
+  * lint: add more test cases for E59: special cases (conf, git url), with and without option `--with-check-upstream` [#5561 @rjbou]
 
 ### Engine
   * Add a test filtering mechanism [#6105 @Keryan-dev]

tests/reftests/lint.test

@@ -851,9 +851,48 @@ license: "ISC"
 dev-repo: "hg+https://[email protected]"
 bug-reports: "https://nobug"
 url { src:"an-archive.tgz" }
+### opam lint ./lint.opam
+${BASEDIR}/lint.opam: Passed.
 ### opam lint ./lint.opam --check-upstream
 ${BASEDIR}/lint.opam: Warnings.
            warning 59: url doesn't contain a checksum
+### <lint.opam>
+opam-version: "2.0"
+synopsis: "A word"
+description: "Two words."
+authors: "the testing team"
+homepage: "egapemoh"
+maintainer: "[email protected]"
+license: "ISC"
+dev-repo: "hg+https://[email protected]"
+bug-reports: "https://nobug"
+url { src:"an-archive.tgz" }
+flags: conf
+### # package with conf flag
+### opam lint ./lint.opam
+${BASEDIR}/lint.opam: Errors.
+             error 46: Package is flagged "conf" but has source, install or remove instructions
+# Return code 1 #
+### opam lint ./lint.opam --check-upstream
+${BASEDIR}/lint.opam: Errors.
+             error 46: Package is flagged "conf" but has source, install or remove instructions
+# Return code 1 #
+### <lint.opam>
+opam-version: "2.0"
+synopsis: "A word"
+description: "Two words."
+authors: "the testing team"
+homepage: "egapemoh"
+maintainer: "[email protected]"
+license: "ISC"
+dev-repo: "hg+https://[email protected]"
+bug-reports: "https://nobug"
+url { src:"git+https://a/repo" }
+### # package with git url
+### opam lint ./lint.opam
+${BASEDIR}/lint.opam: Passed.
+### opam lint ./lint.opam --check-upstream
+${BASEDIR}/lint.opam: Passed.
 ### : E60: Upstream check failed
 ### <lint.opam>
 opam-version: "2.0"