test: expand Molecule coverage for exporter behavior

Cover lineinfile and YAML behavior for default exporters, skipped
defaults, exporters without IDs, duplicate definitions, path and host
overrides, path-prefix precedence, and inherited label overrides.

Verify YAML handling of null documents, multiple files, labeled and
unlabeled groups, and duplicate targets.

Add test coverage for command and shell handlers using run-once,
per-host, disabled, and non-become configurations.

5 files changed, 416 insertions, 23 deletions

diff --git a/molecule/default/converge.yml b/molecule/default/converge.yml
index f882c44..59d63bc 100644
--- a/molecule/default/converge.yml
+++ b/molecule/default/converge.yml
@@ -4,12 +4,6 @@
 - name: Lineinfile bootstrap and subsequent hosts
   hosts: application
   pre_tasks:
-    - name: Create test user
-      ansible.builtin.user:
-        name: prometheus
-      become: true
-      delegate_to: "{{ prometheus_target_host }}"
-
     - name: Create lineinfile bootstrap target
       ansible.builtin.copy:
         dest: /opt/lineinfile_bootstrap.yml
@@ -182,23 +176,6 @@
 ################################################################################
 - name: YAML subsequent hosts and parallel writes
   hosts: application_group
-  pre_tasks:
-    - name: Create yaml parallel target
-      ansible.builtin.copy:
-        dest: "{{ item }}"
-        mode: "0644"
-        content: |
-          - labels:
-              job: node
-            targets:
-              - existing:9100
-        force: true
-      delegate_to: "{{ prometheus_target_host }}"
-      run_once: true
-      loop:
-        - /opt/yaml_parallel.yml
-        - /opt/yaml_parallel_second.yml
-
   vars:
     prometheus_target_host: prometheus
     prometheus_target_strategy: yaml
@@ -495,3 +472,274 @@
       prometheus_target_exporter:
         - path: /opt/hook_target.yml
           host: "{{ inventory_hostname }}"
+
+################################################################################
+################################################################################
+- name: Lineinfile exporter resolution matrix
+  hosts: application
+  pre_tasks:
+    - name: Create lineinfile resolution target files
+      ansible.builtin.copy:
+        dest: "{{ item }}"
+        content: ""
+        mode: "0644"
+        force: false
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+      loop:
+        - /opt/lineinfile_defaults.yml
+        - /opt/lineinfile_no_id.yml
+        - /opt/lineinfile_override.yml
+        - /opt/lineinfile_skipped.yml
+
+    - name: Create lineinfile default prefix directory
+      ansible.builtin.file:
+        path: /opt/lineinfile-prefix
+        state: directory
+        mode: "0755"
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+
+    - name: Create lineinfile prefixed target
+      ansible.builtin.copy:
+        dest: /opt/lineinfile-prefix/default-prefix.yml
+        content: ""
+        mode: "0644"
+        force: false
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_exporter_target_prefix: /opt/
+    prometheus_target_exporter_defaults:
+      inherited:
+        path: lineinfile_defaults.yml
+        host: inherited-default
+      default_only:
+        path: lineinfile_defaults.yml
+        host: appended-default
+      overridden:
+        path: unused.yml
+        host: unused-host
+      prefixed:
+        path: default-prefix.yml
+        host: prefixed-default
+        path_prefix: /opt/lineinfile-prefix/
+    prometheus_target_default_exporters:
+      - id: default_only
+
+  roles:
+    - role: kliwniloc.prometheus_target
+      prometheus_target_strategy_lineinfile_prefix: "- "
+      prometheus_target_exporter:
+        - id: inherited
+        - id: inherited
+        - path: lineinfile_no_id.yml
+          host: no-id
+        - id: overridden
+          path: /opt/lineinfile_override.yml
+          path_prefix: ""
+          host: item-override
+        - id: prefixed
+
+################################################################################
+################################################################################
+- name: Lineinfile skips default exporters
+  hosts: application
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_skip_default_exporters: true
+    prometheus_target_exporter_defaults:
+      skipped:
+        path: /opt/lineinfile_skipped.yml
+        host: must-not-appear
+    prometheus_target_default_exporters:
+      - id: skipped
+
+  roles:
+    - role: kliwniloc.prometheus_target
+
+################################################################################
+################################################################################
+- name: YAML exporter resolution matrix
+  hosts: application
+  pre_tasks:
+    - name: Create YAML resolution target files
+      ansible.builtin.copy:
+        dest: "{{ item.path }}"
+        content: "{{ item.content }}"
+        mode: "0644"
+        force: false
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+      loop:
+        - path: /opt/yaml_defaults.yml
+          content: ""
+        - path: /opt/yaml_no_id.yml
+          content: ""
+        - path: /opt/yaml_override.yml
+          content: ""
+        - path: /opt/yaml_null.yml
+          content: "~\n"
+        - path: /opt/yaml_skipped.yml
+          content: ""
+
+    - name: Create YAML default prefix directory
+      ansible.builtin.file:
+        path: /opt/yaml-prefix
+        state: directory
+        mode: "0755"
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+
+    - name: Create YAML prefixed target
+      ansible.builtin.copy:
+        dest: /opt/yaml-prefix/default-prefix.yml
+        content: ""
+        mode: "0644"
+        force: false
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_strategy: yaml
+    prometheus_target_exporter_target_prefix: /opt/
+    prometheus_target_exporter_defaults:
+      inherited:
+        path: yaml_defaults.yml
+        host: inherited-default:9700
+        labels:
+          job: inherited
+          environment: production
+      default_only:
+        path: yaml_defaults.yml
+        host: appended-default:9701
+        labels:
+          job: default
+      overridden:
+        path: unused.yml
+        host: unused-host
+        labels:
+          job: unused
+      prefixed:
+        path: default-prefix.yml
+        host: prefixed-default:9702
+        path_prefix: /opt/yaml-prefix/
+        labels:
+          job: prefixed
+    prometheus_target_default_exporters:
+      - id: default_only
+
+  roles:
+    - role: kliwniloc.prometheus_target
+      prometheus_target_exporter:
+        - id: inherited
+          host: application:9700
+          labels:
+            environment: staging
+        - id: inherited
+          host: application:9700
+          labels:
+            environment: staging
+        - path: yaml_no_id.yml
+          host: no-id:9700
+          labels:
+            job: no-id
+        - id: overridden
+          path: /opt/yaml_override.yml
+          path_prefix: ""
+          host: item-override:9700
+          labels:
+            job: override
+        - id: prefixed
+        - path: yaml_null.yml
+          host: from-null:9700
+
+################################################################################
+################################################################################
+- name: YAML skips default exporters
+  hosts: application
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_strategy: yaml
+    prometheus_target_skip_default_exporters: true
+    prometheus_target_exporter_defaults:
+      skipped:
+        path: /opt/yaml_skipped.yml
+        host: must-not-appear:9700
+        labels:
+          job: skipped
+    prometheus_target_default_exporters:
+      - id: skipped
+
+  roles:
+    - role: kliwniloc.prometheus_target
+
+################################################################################
+################################################################################
+- name: Handler execution matrix
+  hosts: application_group
+  pre_tasks:
+    - name: Create handler matrix target
+      ansible.builtin.copy:
+        dest: /opt/handler_matrix.yml
+        content: ""
+        mode: "0644"
+        force: false
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+      run_once: true
+
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_handler_command_enabled: true
+    prometheus_target_handler_command_become: false
+    prometheus_target_handler_command_run_once: false
+    prometheus_target_handler_command:
+      cmd: "touch /tmp/command-handler-{{ inventory_hostname }}"
+      creates: "/tmp/command-handler-{{ inventory_hostname }}"
+    prometheus_target_handler_shell_enabled: true
+    prometheus_target_handler_shell_become: false
+    prometheus_target_handler_shell_run_once: true
+    prometheus_target_handler_shell:
+      cmd: touch /tmp/shell-handler-run-once
+      creates: /tmp/shell-handler-run-once
+
+  roles:
+    - role: kliwniloc.prometheus_target
+      prometheus_target_strategy_lineinfile_prefix: "- "
+      prometheus_target_exporter:
+        - path: /opt/handler_matrix.yml
+          host: "{{ inventory_hostname }}"
+
+################################################################################
+################################################################################
+- name: Disabled handlers do not execute
+  hosts: application
+  pre_tasks:
+    - name: Create disabled handler target
+      ansible.builtin.copy:
+        dest: /opt/handler_disabled.yml
+        content: ""
+        mode: "0644"
+        force: false
+      become: true
+      delegate_to: "{{ prometheus_target_host }}"
+
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_handler_command_enabled: false
+    prometheus_target_handler_command:
+      cmd: touch /tmp/disabled-command-handler
+    prometheus_target_handler_shell_enabled: false
+    prometheus_target_handler_shell:
+      cmd: touch /tmp/disabled-shell-handler
+
+  roles:
+    - role: kliwniloc.prometheus_target
+      prometheus_target_strategy_lineinfile_prefix: "- "
+      prometheus_target_exporter:
+        - path: /opt/handler_disabled.yml
+          host: application
diff --git a/molecule/default/molecule.yml b/molecule/default/molecule.yml
index d143303..04d4391 100644
--- a/molecule/default/molecule.yml
+++ b/molecule/default/molecule.yml
@@ -53,6 +53,7 @@ platforms:
 provisioner:
   name: ansible
   playbooks:
+    prepare: prepare.yml
     converge: ${MOLECULE_PLAYBOOK:-converge.yml}
 
 verifier:
diff --git a/molecule/default/prepare.yml b/molecule/default/prepare.yml
new file mode 100644
index 0000000..70764e7
--- /dev/null
+++ b/molecule/default/prepare.yml
@@ -0,0 +1,55 @@
+---
+- name: Prepare Prometheus target fixtures
+  hosts: prometheus
+  gather_facts: false
+  become: true
+
+  tasks:
+    - name: Create Prometheus test user
+      ansible.builtin.user:
+        name: prometheus
+
+    - name: Reset fixtures that exercise parallel writes
+      ansible.builtin.copy:
+        dest: "{{ item }}"
+        mode: "0644"
+        content: |
+          - labels:
+              job: node
+            targets:
+              - existing:9100
+      loop:
+        - /opt/yaml_parallel.yml
+        - /opt/yaml_parallel_second.yml
+
+    # These are intentionally not consumed yet. They provide stable starting
+    # states for the planned exporter state/removal coverage in both strategies.
+    - name: Prepare future YAML removal fixture
+      ansible.builtin.copy:
+        dest: /opt/yaml_state_removal.yml
+        mode: "0644"
+        content: |
+          - labels:
+              job: shared
+            targets:
+              - keep:9100
+              - remove:9100
+          - labels:
+              job: remove_last
+            targets:
+              - remove:9200
+
+    - name: Prepare future lineinfile removal fixture
+      ansible.builtin.copy:
+        dest: /opt/lineinfile_state_removal.yml
+        mode: "0644"
+        content: |
+          - labels:
+              job: shared
+            targets:
+              - keep:9100
+              - remove:9100
+          - labels:
+              job: remove_last
+            targets:
+              - remove:9200
diff --git a/molecule/default/tests/test_lineinfile_strategy.py b/molecule/default/tests/test_lineinfile_strategy.py
index b75a656..770459e 100644
--- a/molecule/default/tests/test_lineinfile_strategy.py
+++ b/molecule/default/tests/test_lineinfile_strategy.py
@@ -92,3 +92,41 @@ def test_lineinfile_hooks_still_run(host):
 
     assert host.file("/opt/hook1").exists
     assert host.file("/opt/hook2").content_string == "hello\nhello\nhello\nhello\n"
+
+
+def test_lineinfile_exporter_defaults_overrides_and_duplicates(host):
+    assert read_yaml_file(host, "/opt/lineinfile_defaults.yml") == [
+        "inherited-default",
+        "appended-default",
+    ]
+    assert read_yaml_file(host, "/opt/lineinfile_no_id.yml") == ["no-id"]
+    assert read_yaml_file(host, "/opt/lineinfile_override.yml") == ["item-override"]
+    assert read_yaml_file(host, "/opt/lineinfile-prefix/default-prefix.yml") == [
+        "prefixed-default"
+    ]
+
+
+def test_lineinfile_skip_default_exporters(host):
+    assert read_file(host, "/opt/lineinfile_skipped.yml").content_string == ""
+
+
+def test_handler_run_once_and_per_host_modes(host):
+    for application in ["application", "application2", "application3", "application4"]:
+        assert host.file(f"/tmp/command-handler-{application}").exists
+
+    assert host.file("/tmp/shell-handler-run-once").exists
+
+
+def test_disabled_handlers_do_not_run(host):
+    assert not host.file("/tmp/disabled-command-handler").exists
+    assert not host.file("/tmp/disabled-shell-handler").exists
+
+
+def test_future_lineinfile_removal_fixture_is_untouched(host):
+    assert read_yaml_file(host, "/opt/lineinfile_state_removal.yml") == [
+        {
+            "labels": {"job": "shared"},
+            "targets": ["keep:9100", "remove:9100"],
+        },
+        {"labels": {"job": "remove_last"}, "targets": ["remove:9200"]},
+    ]
diff --git a/molecule/default/tests/test_yaml_strategy.py b/molecule/default/tests/test_yaml_strategy.py
index 7ba834e..c3d0dd9 100644
--- a/molecule/default/tests/test_yaml_strategy.py
+++ b/molecule/default/tests/test_yaml_strategy.py
@@ -92,6 +92,12 @@ def test_yaml_output_remains_parseable_after_all_operations(host):
         "/opt/yaml_branch_matrix.yml",
         "/opt/yaml_missing_labeled.yml",
         "/opt/yaml_missing_unlabeled.yml",
+        "/opt/yaml_defaults.yml",
+        "/opt/yaml_no_id.yml",
+        "/opt/yaml_override.yml",
+        "/opt/yaml_null.yml",
+        "/opt/yaml-prefix/default-prefix.yml",
+        "/opt/yaml_state_removal.yml",
     ]:
         assert read_yaml_file(host, path) is not None
 
@@ -154,3 +160,48 @@ def test_yaml_branch_matrix_creates_missing_file_groups_for_labeled_and_unlabele
     assert read_yaml_file(host, "/opt/yaml_missing_unlabeled.yml") == [
         {"targets": ["application4:9601"]}
     ]
+
+
+def test_yaml_exporter_defaults_merge_labels_and_deduplicate(host):
+    groups = read_yaml_file(host, "/opt/yaml_defaults.yml")
+
+    assert get_group_by_labels(
+        groups, {"job": "inherited", "environment": "staging"}
+    )["targets"] == ["application:9700"]
+    assert get_group_by_labels(groups, {"job": "default"})["targets"] == [
+        "appended-default:9701"
+    ]
+
+
+def test_yaml_exporter_without_id_and_item_overrides(host):
+    assert read_yaml_file(host, "/opt/yaml_no_id.yml") == [
+        {"labels": {"job": "no-id"}, "targets": ["no-id:9700"]}
+    ]
+    assert read_yaml_file(host, "/opt/yaml_override.yml") == [
+        {"labels": {"job": "override"}, "targets": ["item-override:9700"]}
+    ]
+    assert read_yaml_file(host, "/opt/yaml-prefix/default-prefix.yml") == [
+        {"labels": {"job": "prefixed"}, "targets": ["prefixed-default:9702"]}
+    ]
+
+
+def test_yaml_null_document_is_initialized(host):
+    assert read_yaml_file(host, "/opt/yaml_null.yml") == [
+        {"targets": ["from-null:9700"]}
+    ]
+
+
+def test_yaml_skip_default_exporters(host):
+    target = host.file("/opt/yaml_skipped.yml")
+    assert target.exists
+    assert target.content_string == ""
+
+
+def test_future_yaml_removal_fixture_is_untouched(host):
+    assert read_yaml_file(host, "/opt/yaml_state_removal.yml") == [
+        {
+            "labels": {"job": "shared"},
+            "targets": ["keep:9100", "remove:9100"],
+        },
+        {"labels": {"job": "remove_last"}, "targets": ["remove:9200"]},
+    ]