test: building on an air-gapped system (alire-project#1760)

* Add test for offline build

* Move constraints to YAML file

* Remove redundant build check

* Change crates from git repos to .tgz archives

testsuite/tests/workflows/air-gapping/my_index/index/he/hello/hello-1.0.1.toml

@@ -0,0 +1,11 @@
+description = "\"Hello, world!\" demonstration project"
+name = "hello"
+version = "1.0.1"
+maintainers = ["[email protected]", "[email protected]"]
+maintainers-logins = ["mylogin"]
+
+[[depends-on]]
+libhello = "^1.0"
+
+[origin]
+url = "file:../../../crates/hello.tgz"

testsuite/tests/workflows/air-gapping/my_index/index/index.toml

@@ -0,0 +1 @@
+version = "1.1"

testsuite/tests/workflows/air-gapping/my_index/index/li/libhello/libhello-1.0.0.toml

@@ -0,0 +1,8 @@
+description = "\"Hello, world!\" demonstration project support library"
+name = "libhello"
+version = "1.0.0"
+maintainers = ["[email protected]"]
+maintainers-logins = ["mylogin"]
+
+[origin]
+url = "file:../../../crates/libhello.tgz"

testsuite/tests/workflows/air-gapping/test.py

@@ -0,0 +1,83 @@
+"""
+Test fetching a crate online, and subsequently building offline.
+"""
+
+
+import os
+import shutil
+import subprocess
+
+from drivers.alr import run_alr
+from drivers.asserts import assert_eq, assert_match
+
+
+# Mock tar, git, curl, gprbuild etc. with dummy scripts
+os.mkdir("path-dir")
+os.chdir("path-dir")
+for executable in ("tar", "git", "hg", "svn", "curl", "gprbuild"):
+    with open(executable, "w") as f:
+        f.write("\n".join([
+            "#!/usr/bin/env python",
+            "import sys",
+            "print('Mocked command called')",
+            "sys.exit(1)"
+        ]))
+    os.chmod(executable, 0o764)
+os.environ["PATH"] = f'{os.getcwd()}{os.pathsep}{os.environ["PATH"]}'
+os.chdir("..")
+
+
+# Run `alr get hello`. This will fail because tar is unavailable.
+p = run_alr("get", "hello", quiet=False, complain_on_error=False)
+assert_match(".*Mocked command called", p.out)
+assert_match(".*Deployment of path .* to .* failed", p.out)
+
+# Disable tar mocking and run `alr get hello` to 'download' the crate and its
+# dependencies.
+os.remove(os.path.join("path-dir", "tar"))
+p = run_alr("get", "hello", quiet=False)
+assert_match(r".*hello=1\.0\.1 successfully retrieved", p.out)
+assert_match(r".*\+ libhello 1\.0\.0 \(new\)", p.out)
+
+# Re-enable tar mocking and make the index unavailable to simulate disconnection
+# from the network
+shutil.copy(os.path.join("path-dir", "curl"), os.path.join("path-dir", "tar"))
+shutil.move("my_index", "somewhere_else")
+
+# Simulate transferring to a different system by clearing the alr-config
+# directory (we keep settings.toml, since it just does various things to isolate
+# the test environment) and changing the absolute path of the crate directory.
+for f in os.listdir("alr-config"):
+    if f != "settings.toml":
+        shutil.rmtree(os.path.join("alr-config", f))
+shutil.move(f"hello_1.0.1_filesystem", "hello")
+
+# Run `alr build`. This will fail because gprbuild is unavailable.
+os.chdir(f"hello")
+p = run_alr("build", quiet=False, complain_on_error=False)
+assert_match(".*Mocked command called", p.out)
+assert_match(r'.*Command \["gprbuild", .*\] exited with code 1', p.out)
+
+# Disable gprbuild mocking and run `alr build` to build the crate (with tar
+# mocking still enabled to check it doesn't try to fetch anything else)
+os.remove(os.path.join("..", "path-dir", "gprbuild"))
+p = run_alr("build", quiet=False)
+
+# Check the built binary works as expected
+assert_eq(
+    b"Hello, world!\n",
+    subprocess.run([os.path.join("obj", "hello")], capture_output=True).stdout
+)
+
+# Clear out the downloaded dependencies, and verify that `alr build` then
+# attempts (and fails) to re-fetch them
+shutil.rmtree(os.path.join("alire", "cache", "dependencies"))
+p = run_alr("build", quiet=False, complain_on_error=False)
+assert_match(
+    ".*Filesystem crate is neither a folder nor a source archive: ",
+    p.out
+)
+assert_match(".*Deployment of path .* to .* failed", p.out)
+
+
+print("SUCCESS")

testsuite/tests/workflows/air-gapping/test.yaml

@@ -0,0 +1,10 @@
+driver: python-script
+# We need 'dependencies.shared=false' anyway for dependencies to be packaged
+# inside the workspace, so we only run in sandboxed mode.
+build_mode: sandboxed
+control:
+    # Mocking commands this way doesn't work on Windows
+    - [SKIP, "skip_unix", "Test is Unix-only"]
+indexes:
+    my_index:
+        in_fixtures: false