From 12c4f9bbd0b11fdaf91cfd4deb440c6b084e2da2 Mon Sep 17 00:00:00 2001
From: Alejandro R Mosteo <amosteo@unizar.es>
Date: Mon, 24 Feb 2025 15:08:36 +0100
Subject: [PATCH] feat: test ensuring no trivial rebuilds (#1863)

* feat: test ensuring no trivial rebuilds

* Fix test on Windows
---
 testsuite/drivers/helpers.py                  |  8 +++++
 testsuite/tests/build/no-rebuild/test.py      | 30 +++++++++++++++++++
 testsuite/tests/build/no-rebuild/test.yaml    |  5 ++++
 .../tests/crate_config/no-rebuilds/test.py    |  3 +-
 4 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 testsuite/tests/build/no-rebuild/test.py
 create mode 100644 testsuite/tests/build/no-rebuild/test.yaml

diff --git a/testsuite/drivers/helpers.py b/testsuite/drivers/helpers.py
index 9ae92a69..a1911836 100644
--- a/testsuite/drivers/helpers.py
+++ b/testsuite/drivers/helpers.py
@@ -296,6 +296,7 @@ def neutral_path(path : str) -> str:
     """
     return path.replace('\\', '/')
 
+
 def which(exec : str) -> str:
     """
     Return the full path to an executable if it can be found in PATH, or ""
@@ -307,6 +308,13 @@ def which(exec : str) -> str:
     return shutil.which(exec)
 
 
+def exe_name(exec : str) -> str:
+    """
+    Return the executable name with ".exe" appended on Windows.
+    """
+    return f"{exec}.exe" if on_windows() else exec
+
+
 class FileLock():
     """
     A filesystem-level lock for tests executed from different threads but
diff --git a/testsuite/tests/build/no-rebuild/test.py b/testsuite/tests/build/no-rebuild/test.py
new file mode 100644
index 00000000..812a8bc8
--- /dev/null
+++ b/testsuite/tests/build/no-rebuild/test.py
@@ -0,0 +1,30 @@
+"""
+Ensure that no rebuild happens when `alr build` is invoked twice. Reports like
+https://github.com/alire-project/alire/issues/1798 hint at a problem in gprbuild
+itself, but this should not arise at least on simple crates.
+
+This test differs from crate_config/no-rebuilds in that here we have dependencies.
+"""
+
+from drivers.alr import alr_with, init_local_crate, run_alr
+from drivers.asserts import assert_substring
+from drivers.helpers import exe_name
+
+# Basic check in which building twice should not trigger a rebuild
+
+init_local_crate()
+alr_with("libhello")
+run_alr("build")
+p = run_alr("build", quiet=False)
+assert_substring (f'gprbuild: "{exe_name("xxx")}" up to date', p.out)
+
+# Check that removing and re-adding a dependency does not trigger a rebuild
+# (since the build folders already exist).
+
+run_alr("with", "--del", "libhello")
+run_alr("with", "libhello")
+p = run_alr("build", quiet=False)
+assert_substring (f'gprbuild: "{exe_name("xxx")}" up to date', p.out)
+
+
+print("SUCCESS")
diff --git a/testsuite/tests/build/no-rebuild/test.yaml b/testsuite/tests/build/no-rebuild/test.yaml
new file mode 100644
index 00000000..78b8b224
--- /dev/null
+++ b/testsuite/tests/build/no-rebuild/test.yaml
@@ -0,0 +1,5 @@
+driver: python-script
+build_mode: shared
+indexes:
+    basic_index:
+        in_fixtures: true
diff --git a/testsuite/tests/crate_config/no-rebuilds/test.py b/testsuite/tests/crate_config/no-rebuilds/test.py
index 7715f9c2..1ff17724 100644
--- a/testsuite/tests/crate_config/no-rebuilds/test.py
+++ b/testsuite/tests/crate_config/no-rebuilds/test.py
@@ -2,9 +2,8 @@
 Ensure that no unnecessary rebuilds happend due to crate config generation
 """
 
-from drivers.alr import alr_with, init_local_crate, run_alr
+from drivers.alr import init_local_crate, run_alr
 from drivers.asserts import assert_match
-from drivers.helpers import prepend_to_file
 
 init_local_crate()
 run_alr("build") # First build
-- 
2.39.5