test: gen-only e2e scenarios for opt-in workflow generators

e2e/harness/multistep.go

@@ -70,15 +70,18 @@ type StepExpect struct {
 }
 
 // WorkflowFileExpect asserts a generated workflow file contains/excludes
-// specific substrings. Verifies manifest fields make it into the emitted
-// YAML, orthogonal to behavior checks (state/jobs/etc.) which observe the
-// run outcome. Used for features whose effect is purely the generated
-// workflow shape (#92 concurrency, #97 timeout-minutes, #101/#102 push
-// retry loops).
+// specific substrings, or asserts the file is absent entirely. Verifies
+// manifest fields make it into the emitted YAML, orthogonal to behavior
+// checks (state/jobs/etc.) which observe the run outcome. NotExists covers
+// the conditional-generation case where a feature suppresses a whole file
+// (for example the hotfix workflow when fewer than two environments exist).
+// Used for features whose effect is purely the generated workflow shape
+// (#92 concurrency, #97 timeout-minutes, #101/#102 push retry loops).
 type WorkflowFileExpect struct {
 	Path        string   `yaml:"path"`                   // Path inside the test repo (e.g., ".github/workflows/orchestrate.yaml")
 	Contains    []string `yaml:"contains,omitempty"`     // Substrings that must appear
 	NotContains []string `yaml:"not_contains,omitempty"` // Substrings that must NOT appear
+	NotExists   bool     `yaml:"not_exists,omitempty"`   // When true, the file must NOT exist
 }
 
 // StateExpect defines expected state for an environment

e2e/harness/runner.go

@@ -725,6 +725,12 @@ func (r *Runner) assertWorkflowFile(ctx context.Context, expect WorkflowFileExpe
 	if reader != nil {
 		_, _ = io.Copy(&content, reader)
 	}
+	if expect.NotExists {
+		if exitCode == 0 {
+			return []error{fmt.Errorf("workflow file %s should not exist but was found", expect.Path)}
+		}
+		return nil
+	}
 	if exitCode != 0 {
 		return []error{fmt.Errorf("workflow file not found: %s", expect.Path)}
 	}

e2e/harness/scenario.go

@@ -45,6 +45,18 @@ type Config struct {
 	// job-level environment: key. Mirrors internal/config EnvironmentConfig.
 	// Keyed by env name so future per-env keys extend additively.
 	EnvironmentConfig map[string]EnvEnvironmentConfig `yaml:"environment_config,omitempty"`
+	// Validate, ValidateCheck, MergeQueue, PRPreview, Notify, and External carry
+	// the optional generator features through to the generated manifest untouched.
+	// Each uses a generic map (rather than a typed struct) so the harness stays
+	// decoupled from the generator's struct shapes while preserving every key
+	// across the marshal round-trip. As the generator gains new keys under any of
+	// these blocks, scenarios can exercise them without a harness change.
+	Validate      map[string]any   `yaml:"validate,omitempty"`
+	ValidateCheck map[string]any   `yaml:"validate_check,omitempty"`
+	MergeQueue    map[string]any   `yaml:"merge_queue,omitempty"`
+	PRPreview     map[string]any   `yaml:"pr_preview,omitempty"`
+	Notify        map[string]any   `yaml:"notify,omitempty"`
+	External      []map[string]any `yaml:"external,omitempty"`
 }
 
 // EnvEnvironmentConfig mirrors internal/config.EnvironmentConfig's gha_environment

e2e/scenarios/14-validate-check.yaml

@@ -0,0 +1,38 @@
+name: "Validate Check Workflow"
+description: |
+  Verifies that enabling validate_check emits the standalone
+  cascade-validate.yaml workflow that runs the manifest parse on pull
+  requests touching the manifest file (#90).
+
+  Generator-output verification only.
+
+config:
+  trunk_branch: main
+  environments: [dev]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys: []
+  validate_check:
+    enabled: true
+
+steps:
+  - name: "Initial commit; assert cascade-validate.yaml is generated"
+    action: commit
+    commit:
+      message: "feat: add app"
+      files:
+        src/app.go: |
+          package main
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/cascade-validate.yaml"
+          contains:
+            - "name: Validate Manifest"
+            - "pull_request:"
+            - "paths:"
+            - ".github/manifest.yaml"
+            - "validate-manifest:"
+            - "cascade parse-config"

e2e/scenarios/15-merge-queue.yaml

@@ -0,0 +1,37 @@
+name: "Merge Queue Workflow"
+description: |
+  Verifies that enabling merge_queue emits the cascade-merge-queue.yaml
+  workflow that validates the manifest and sets up orchestration on
+  merge_group events (#91).
+
+  Generator-output verification only.
+
+config:
+  trunk_branch: main
+  environments: [dev]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys: []
+  merge_queue:
+    enabled: true
+
+steps:
+  - name: "Initial commit; assert cascade-merge-queue.yaml is generated"
+    action: commit
+    commit:
+      message: "feat: add app"
+      files:
+        src/app.go: |
+          package main
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/cascade-merge-queue.yaml"
+          contains:
+            - "merge_group"
+            - "contents: read"
+            - "merge-queue-validate:"
+            - "cascade parse-config"
+            - "cascade --dry-run orchestrate setup"

e2e/scenarios/16-pr-preview.yaml

@@ -0,0 +1,37 @@
+name: "PR Preview Workflow"
+description: |
+  Verifies that enabling pr_preview emits the cascade-pr-preview.yaml
+  workflow that plans a preview on pull requests, with a per-PR
+  concurrency group (#93).
+
+  Generator-output verification only.
+
+config:
+  trunk_branch: main
+  environments: [dev]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys: []
+  pr_preview:
+    enabled: true
+
+steps:
+  - name: "Initial commit; assert cascade-pr-preview.yaml is generated"
+    action: commit
+    commit:
+      message: "feat: add app"
+      files:
+        src/app.go: |
+          package main
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/cascade-pr-preview.yaml"
+          contains:
+            - "name: Cascade PR Preview"
+            - "pull_request:"
+            - "cascade-pr-preview-${{ github.event.pull_request.number }}"
+            - "preview:"
+            - "Plan Preview"

e2e/scenarios/17-validate-callback.yaml

@@ -0,0 +1,37 @@
+name: "Validate Callback Gate"
+description: |
+  Verifies that a top-level validate callback adds a validate job to the
+  generated orchestrate.yaml and gates the build jobs on its success via a
+  needs.validate.result == 'success' condition (#94).
+
+  Generator-output verification only.
+
+config:
+  trunk_branch: main
+  environments: [dev]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys:
+    - name: deploy-dev
+      workflow: deploy.yaml
+      triggers: ["src/**"]
+  validate:
+    run: "echo validate"
+
+steps:
+  - name: "Initial commit; assert validate gate in orchestrate.yaml"
+    action: commit
+    commit:
+      message: "feat: add app"
+      files:
+        src/app.go: |
+          package main
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/orchestrate.yaml"
+          contains:
+            - "validate:"
+            - "needs.validate.result == 'success'"

e2e/scenarios/hotfix/hotfix-generation-threshold.yaml

@@ -0,0 +1,51 @@
+name: "Hotfix Generation Threshold"
+description: |
+  Verifies that a repository with two or more environments generates the
+  cascade-hotfix.yaml workflow with its full set of jobs and the finalize
+  step that records the merge, fix, and base SHAs (#88).
+
+  Generator-output verification only.
+
+config:
+  trunk_branch: main
+  environments: [dev, prod]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys:
+    - name: deploy-dev
+      workflow: deploy.yaml
+      triggers: ["src/**"]
+    - name: deploy-prod
+      workflow: deploy.yaml
+      triggers: ["src/**"]
+
+steps:
+  - name: "Initial commit; assert cascade-hotfix.yaml is generated"
+    action: commit
+    commit:
+      message: "feat: add app"
+      files:
+        src/app.go: |
+          package main
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/cascade-hotfix.yaml"
+          contains:
+            - "workflow_dispatch:"
+            - "type: choice"
+            - "target_env:"
+            - "pull_request:"
+            - "types: [closed]"
+            - "'env/*'"
+            - "group: hotfix-"
+            - "  plan:"
+            - "  apply:"
+            - "  check:"
+            - "  context:"
+            - "  finalize:"
+            - "--merge-sha"
+            - "--fix-sha"
+            - "--base-sha"

e2e/scenarios/hotfix/hotfix-no-hotfix-single-env.yaml

@@ -0,0 +1,33 @@
+name: "Hotfix Single Env Absent"
+description: |
+  Verifies that a repository with a single environment does not generate
+  the cascade-hotfix.yaml workflow, since the hotfix flow only applies once
+  two or more environments exist (#88).
+
+  Generator-output verification only.
+
+config:
+  trunk_branch: main
+  environments: [dev]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys:
+    - name: deploy-dev
+      workflow: deploy.yaml
+      triggers: ["src/**"]
+
+steps:
+  - name: "Initial commit; assert cascade-hotfix.yaml is absent"
+    action: commit
+    commit:
+      message: "feat: add app"
+      files:
+        src/app.go: |
+          package main
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/cascade-hotfix.yaml"
+          not_exists: true