Module records and aliases

Installation records what a module reports about itself. dpm_install_module
opens a module once, writes its version and description to a .meta file in
/var/lib/dpm/metadata/, and records the alternate names it declared in
modules.aliases beside it. dpm_uninstall_module removes both, leaving the
module file in place.

dpm_list_modules reads those records and opens no module. A module with no
record lists with a version of <uninstalled> and still loads when a caller
names it. An unreadable or absent metadata directory costs the listing its
detail and costs nothing else.

Aliases give a module alternate names, declared through the new
dpm_module_aliases contract symbol or added with dpm_add_module_alias. A
name is recorded once: one already serving as an alias, or belonging to an
installed module, is refused rather than repointed. dpm_require matches a
name against the installed modules, then the alias table, then the module
path.

The metadata directory is a fifth override field and the -M flag, and
[modules] metadata in core.conf.

The test suite is four binaries covering context, modules, records, and
aliases, each a ctest case of its own, alongside the CLI cases.

tests/CMakeLists.txt

@@ -15,40 +15,62 @@ foreach(fixture good missing_symbols bad_version)
 endforeach()
 
 # ---------------------------------------------------------------------
-# API test binary — drives libdpm-core.so through its public C API
+# API test binaries — one per area of the library, each its own ctest
+# case, so a failure names the area it happened in
 # ---------------------------------------------------------------------
-add_executable(test_core test_core.cpp)
+foreach(suite context modules metadata aliases)
+    add_executable(test_${suite} test_${suite}.cpp)
 
-target_link_libraries(test_core PRIVATE dpm-core)
+    target_link_libraries(test_${suite} PRIVATE dpm-core)
 
-target_compile_definitions(test_core PRIVATE
-        TEST_FIXTURE_MODULES="${DPM_TEST_FIXTURE_DIR}"
-        TEST_FIXTURE_CONF="${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf"
-        DPM_CORE_VERSION_EXPECTED="${PROJECT_VERSION}"
-)
+    target_include_directories(test_${suite} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
 
-set_target_properties(test_core PROPERTIES
-        RUNTIME_OUTPUT_DIRECTORY ${DPM_TEST_DIR}
-        BUILD_RPATH "$ORIGIN/../lib"
-)
+    target_compile_definitions(test_${suite} PRIVATE
+            TEST_FIXTURE_MODULES="${DPM_TEST_FIXTURE_DIR}"
+            TEST_FIXTURE_CONF="${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf"
+            TEST_FIXTURE_METADATA="${CMAKE_CURRENT_SOURCE_DIR}/fixtures/metadata"
+            TEST_SCRATCH_ROOT="${DPM_TEST_DIR}/scratch"
+            DPM_CORE_VERSION_EXPECTED="${PROJECT_VERSION}"
+    )
 
-foreach(fixture good missing_symbols bad_version)
-    add_dependencies(test_core fixture_${fixture})
+    set_target_properties(test_${suite} PROPERTIES
+            RUNTIME_OUTPUT_DIRECTORY ${DPM_TEST_DIR}
+            BUILD_RPATH "$ORIGIN/../lib"
+    )
+
+    foreach(fixture good missing_symbols bad_version)
+        add_dependencies(test_${suite} fixture_${fixture})
+    endforeach()
+
+    add_test(NAME api_${suite} COMMAND test_${suite})
 endforeach()
 
-add_test(NAME core_api COMMAND test_core)
-
 # ---------------------------------------------------------------------
 # CLI end-to-end tests (the dpm binary is the cheapest full-stack client)
 # ---------------------------------------------------------------------
+set(CLI_FIXTURE_ARGS
+        -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
+        -m ${CMAKE_BINARY_DIR}/modules
+        -M ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/metadata
+)
+
 add_test(NAME cli_help COMMAND dpm --help)
 set_tests_properties(cli_help PROPERTIES PASS_REGULAR_EXPRESSION "Usage: dpm")
 
-add_test(NAME cli_list
-        COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
-                    -m ${CMAKE_BINARY_DIR}/modules --list-modules)
+add_test(NAME cli_help_lists_record_flags COMMAND dpm --help)
+set_tests_properties(cli_help_lists_record_flags PROPERTIES
+        PASS_REGULAR_EXPRESSION "--install-module")
+
+add_test(NAME cli_list COMMAND dpm ${CLI_FIXTURE_ARGS} --list-modules)
 set_tests_properties(cli_list PROPERTIES PASS_REGULAR_EXPRESSION "info")
 
+# The bundled module has no record in the fixture directory, so the
+# listing reports it as uninstalled rather than opening it.
+add_test(NAME cli_list_marks_uninstalled
+        COMMAND dpm ${CLI_FIXTURE_ARGS} --list-modules)
+set_tests_properties(cli_list_marks_uninstalled PROPERTIES
+        PASS_REGULAR_EXPRESSION "<uninstalled>")
+
 add_test(NAME cli_info_version
         COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
                     -m ${CMAKE_BINARY_DIR}/modules -L INFO info version)
@@ -56,11 +78,59 @@ set_tests_properties(cli_info_version PROPERTIES
         PASS_REGULAR_EXPRESSION "libdpm-core\\.so Version: ${PROJECT_VERSION}")
 
 add_test(NAME cli_module_not_found
-        COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
-                    -m ${CMAKE_BINARY_DIR}/modules nonexistent)
+        COMMAND dpm ${CLI_FIXTURE_ARGS} nonexistent)
 set_tests_properties(cli_module_not_found PROPERTIES WILL_FAIL TRUE)
 
 add_test(NAME cli_rejects_invalid_module
         COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
-                    -m ${DPM_TEST_FIXTURE_DIR} missing_symbols)
+                    -m ${DPM_TEST_FIXTURE_DIR}
+                    -M ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/metadata
+                    missing_symbols)
 set_tests_properties(cli_rejects_invalid_module PROPERTIES WILL_FAIL TRUE)
+
+add_test(NAME cli_lists_aliases COMMAND dpm ${CLI_FIXTURE_ARGS} --list-aliases)
+set_tests_properties(cli_lists_aliases PROPERTIES
+        PASS_REGULAR_EXPRESSION "goodie")
+
+add_test(NAME cli_lists_aliases_for_module
+        COMMAND dpm ${CLI_FIXTURE_ARGS} --list-aliases good)
+set_tests_properties(cli_lists_aliases_for_module PROPERTIES
+        PASS_REGULAR_EXPRESSION "gd")
+
+add_test(NAME cli_refuses_duplicate_alias
+        COMMAND dpm ${CLI_FIXTURE_ARGS} --add-alias good goodie)
+set_tests_properties(cli_refuses_duplicate_alias PROPERTIES WILL_FAIL TRUE)
+
+add_test(NAME cli_add_alias_requires_two_arguments
+        COMMAND dpm ${CLI_FIXTURE_ARGS} --add-alias good)
+set_tests_properties(cli_add_alias_requires_two_arguments PROPERTIES
+        WILL_FAIL TRUE)
+
+add_test(NAME cli_uninstall_unrecorded_module
+        COMMAND dpm ${CLI_FIXTURE_ARGS} --uninstall-module nonexistent)
+set_tests_properties(cli_uninstall_unrecorded_module PROPERTIES WILL_FAIL TRUE)
+
+# The install and uninstall round trip writes, so it runs against a
+# scratch directory of its own and the two cases run in order.
+add_test(NAME cli_install_module
+        COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
+                    -m ${CMAKE_BINARY_DIR}/modules
+                    -M ${DPM_TEST_DIR}/scratch/cli
+                    --install-module info)
+
+add_test(NAME cli_lists_installed_module
+        COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
+                    -m ${CMAKE_BINARY_DIR}/modules
+                    -M ${DPM_TEST_DIR}/scratch/cli
+                    --list-modules)
+set_tests_properties(cli_lists_installed_module PROPERTIES
+        PASS_REGULAR_EXPRESSION "Reports and tests libdpm-core"
+        DEPENDS cli_install_module)
+
+add_test(NAME cli_uninstall_module
+        COMMAND dpm -c ${CMAKE_CURRENT_SOURCE_DIR}/fixtures/conf
+                    -m ${CMAKE_BINARY_DIR}/modules
+                    -M ${DPM_TEST_DIR}/scratch/cli
+                    --uninstall-module info)
+set_tests_properties(cli_uninstall_module PROPERTIES
+        DEPENDS cli_lists_installed_module)