tests: make test assertion a bit more extensible (#22)

* tests: make test assertion a bit more extensible

Poetry buildpack works not only with Paketo CPython buildpack as
dependency, but with any other CPython buildpack that observes the
CPython buildpack's API

* default_test.go: rm Paketo CPython specific assert

Author: Arjun Sreedharan

integration/default_test.go

@@ -87,7 +87,6 @@ func testDefault(t *testing.T, context spec.G, it spec.S) {
 				MatchRegexp(fmt.Sprintf(`    PYTHONPATH -> "\/layers\/%s\/poetry\/lib\/python\d+\.\d+\/site-packages:\$PYTHONPATH"`, strings.ReplaceAll(buildpackInfo.Buildpack.ID, "/", "_"))),
 			))
 			Expect(logs).To(ContainLines(
-				MatchRegexp(`Paketo CPython Buildpack \d+\.\d+\.\d+`),
 				"  Resolving CPython version",
 				"    Candidate version sources (in priority order):",
 				`      pyproject.toml -> "3.8.*"`,