Expose last pipeline details in API response when getting a single commit

Closes #35692.

changelogs/unreleased/expose-last-pipeline-details-in-api-for-single-commit.yml

+---
+title: Expose last pipeline details in API response when getting a single commit
+merge_request: 13521
+author: Mehdi Lahmam (@mehlah)
+type: added

doc/api/commits.md

@@ -181,6 +181,12 @@ Example response:
   "parent_ids": [
     "ae1d9fb46aa2b07ee9836d49862ec4e2c46fbbba"
   ],
+  "last_pipeline" : {
+    "id": 8,
+    "ref": "master",
+    "sha": "2dc6aa325a317eda67812f05600bdf0fcdc70ab0"
+    "status": "created"
+  }
   "stats": {
     "additions": 15,
     "deletions": 10,

lib/api/entities.rb

@@ -234,6 +234,7 @@ module API
     class RepoCommitDetail < RepoCommit
       expose :stats, using: Entities::RepoCommitStats
       expose :status
+      expose :last_pipeline, using: 'API::Entities::PipelineBasic'
     end
 
     class RepoBranch < Grape::Entity

spec/fixtures/api/schemas/public_api/v4/commit/detail.json

@@ -5,11 +5,18 @@
     {
       "required" : [
         "stats",
-        "status"
+        "status",
+        "last_pipeline"
       ],
       "properties": {
         "stats": { "$ref": "../commit_stats.json" },
-        "status": { "type": ["string", "null"] }
+        "status": { "type": ["string", "null"] },
+        "last_pipeline": {
+          "oneOf": [
+            { "type": "null" },
+            { "$ref": "../pipeline/basic.json" }
+          ]
+        }
       }
     }
   ]

spec/fixtures/api/schemas/public_api/v4/pipeline/basic.json

+{
+  "type": "object",
+  "required" : [
+    "id",
+    "sha",
+    "ref",
+    "status"
+  ],
+  "properties" : {
+    "id": { "type": "integer" },
+    "sha": { "type": "string" },
+    "ref": { "type": "string" },
+    "status": { "type": "string" }
+  },
+  "additionalProperties": false
+}

spec/requests/api/commits_spec.rb

@@ -491,6 +491,7 @@ describe API::Commits do
         expect(json_response['stats']['deletions']).to eq(commit.stats.deletions)
         expect(json_response['stats']['total']).to eq(commit.stats.total)
         expect(json_response['status']).to be_nil
+        expect(json_response['last_pipeline']).to be_nil
       end
 
       context 'when ref does not exist' do
@@ -573,6 +574,10 @@ describe API::Commits do
           expect(response).to have_http_status(200)
           expect(response).to match_response_schema('public_api/v4/commit/detail')
           expect(json_response['status']).to eq('created')
+          expect(json_response['last_pipeline']['id']).to eq(pipeline.id)
+          expect(json_response['last_pipeline']['ref']).to eq(pipeline.ref)
+          expect(json_response['last_pipeline']['sha']).to eq(pipeline.sha)
+          expect(json_response['last_pipeline']['status']).to eq(pipeline.status)
         end
 
         context 'when pipeline succeeds' do