test: copied build_fake_container_fixture() from bib

This is a very sad commit, it copies the code to make a fake
container with a faked osbuild.

The bright side is that the plan is to rewrite these helpers
in go and then we can just have a shared testutil module that
can be imported from both bib/ibcli.

And/or the two repos will merge and its just a (simple) test
helper. But I do not feel good (at all) about this.

test/conftest.py

@@ -1,4 +1,5 @@
 import subprocess
+import textwrap
 
 import pytest
 
@@ -15,3 +16,39 @@ def build_container_fixture():
         "-t", container_tag,
     ])
     return container_tag
+
+
+# XXX: copied from bib
+@pytest.fixture(name="build_fake_container", scope="session")
+def build_fake_container_fixture(tmpdir_factory, build_container):
+    """Build a container with a fake osbuild and returns the name"""
+    tmp_path = tmpdir_factory.mktemp("build-fake-container")
+
+    fake_osbuild_path = tmp_path / "fake-osbuild"
+    fake_osbuild_path.write_text(textwrap.dedent("""\
+    #!/bin/bash -e
+
+    # injest generated manifest from the images library, if we do not
+    # do this images may fail with "broken" pipe errors
+    cat - >/dev/null
+
+    mkdir -p /output/qcow2
+    echo "fake-disk.qcow2" > /output/qcow2/disk.qcow2
+
+    """), encoding="utf8")
+
+    cntf_path = tmp_path / "Containerfile"
+
+    cntf_path.write_text(textwrap.dedent(f"""\n
+    FROM {build_container}
+    COPY fake-osbuild /usr/bin/osbuild
+    RUN chmod 755 /usr/bin/osbuild
+    """), encoding="utf8")
+
+    container_tag = "bootc-image-builder-test-faked-osbuild"
+    subprocess.check_call([
+        "podman", "build",
+        "-t", container_tag,
+        tmp_path,
+    ])
+    return container_tag