add tests for cancellation while building

command/build_cancellation_test.go

@@ -0,0 +1,81 @@
+package command
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestBuildCommand_RunContext_CtxCancel(t *testing.T) {
+
+	tests := []struct {
+		name                 string
+		args                 []string
+		parallelPassingTests int
+		expected             int
+	}{
+		{"cancel 1 pending build - parallel=true",
+			[]string{"-parallel=true", filepath.Join(testFixture("parallel"), "1lock-5wg.json")},
+			5,
+			1,
+		},
+		{"cancel in the middle with 2 pending builds - parallel=true",
+			[]string{"-parallel=true", filepath.Join(testFixture("parallel"), "2lock-4wg.json")},
+			4,
+			1,
+		},
+		// {"cancel 1 locked build - debug - parallel=true",
+		// 	[]string{"-parallel=true", "-debug=true", filepath.Join(testFixture("parallel"), "1lock.json")},
+		// 	5,
+		// 	1,
+		// },
+		// {"cancel 2 locked builds - debug - parallel=true",
+		// 	[]string{"-parallel=true", "-debug=true", filepath.Join(testFixture("parallel"), "2lock.json")},
+		// 	4,
+		// 	1,
+		// },
+		// {"cancel 1 locked build - debug - parallel=false",
+		// 	[]string{"-parallel=false", "-debug=true", filepath.Join(testFixture("parallel"), "1lock.json")},
+		// 	5,
+		// 	1,
+		// },
+		// {"cancel 2 locked builds - debug - parallel=false",
+		// 	[]string{"-parallel=false", "-debug=true", filepath.Join(testFixture("parallel"), "2lock.json")},
+		// 	4,
+		// 	1,
+		// },
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			b := NewParallelTestBuilder(tt.parallelPassingTests)
+			locked := &LockedBuilder{unlock: make(chan interface{})}
+			c := &BuildCommand{
+				Meta: testMetaParallel(t, b, locked),
+			}
+
+			ctx, cancelCtx := context.WithCancel(context.Background())
+			codeC := make(chan int)
+			go func() {
+				defer close(codeC)
+				codeC <- c.RunContext(ctx, tt.args)
+			}()
+			b.wg.Wait() // ran `tt.parallelPassingTests` times
+			cancelCtx()
+
+			select {
+			case code := <-codeC:
+				if code != tt.expected {
+					t.Logf("wrong code: %s", cmp.Diff(code, tt.expected))
+					fatalCommand(t, c.Meta)
+				}
+			case <-time.After(15 * time.Second):
+				t.Fatal("deadlock")
+			}
+		})
+	}
+}

command/build_parallel_test.go

@@ -46,7 +46,6 @@ func (b *LockedBuilder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook)
 	select {
 	case <-b.unlock:
 	case <-ctx.Done():
-		panic("crap")
 		return nil, ctx.Err()
 	}
 	return nil, nil
@@ -99,7 +98,7 @@ func TestBuildParallel_1(t *testing.T) {
 
 	args := []string{
 		fmt.Sprintf("-parallel=true"),
-		filepath.Join(testFixture("parallel"), "1lock.json"),
+		filepath.Join(testFixture("parallel"), "1lock-5wg.json"),
 	}
 
 	wg := errgroup.Group{}
@@ -128,7 +127,7 @@ func TestBuildParallel_2(t *testing.T) {
 
 	args := []string{
 		fmt.Sprintf("-parallel-builds=3"),
-		filepath.Join(testFixture("parallel"), "2lock.json"),
+		filepath.Join(testFixture("parallel"), "2lock-4wg"),
 	}
 
 	wg := errgroup.Group{}

command/test-fixtures/parallel/1lock-5wg.json

@@ -0,0 +1,10 @@
+{
+    "builders": [
+        {"type": "lock", "name": "build0"},
+        {"type": "parallel-test", "name": "build1"},
+        {"type": "parallel-test", "name": "build2"},
+        {"type": "parallel-test", "name": "build3"},
+        {"type": "parallel-test", "name": "build4"},
+        {"type": "parallel-test", "name": "build5"}
+    ]
+}

command/test-fixtures/parallel/1lock.json

@@ -1,10 +1,5 @@
 {
     "builders": [
-        {"type": "lock", "name": "build0"},
+        {"type": "lock", "name": "build0"}
-        {"type": "parallel-test", "name": "build1"},
-        {"type": "parallel-test", "name": "build2"},
-        {"type": "parallel-test", "name": "build3"},
-        {"type": "parallel-test", "name": "build4"},
-        {"type": "parallel-test", "name": "build5"}
     ]
 }

command/test-fixtures/parallel/2lock-4wg.json

@@ -0,0 +1,10 @@
+{
+    "builders": [
+        {"type": "lock", "name": "build0"},
+        {"type": "parallel-test", "name": "build1"},
+        {"type": "parallel-test", "name": "build2"},
+        {"type": "lock", "name": "build3"},
+        {"type": "parallel-test", "name": "build4"},
+        {"type": "parallel-test", "name": "build5"}
+    ]
+}

command/test-fixtures/parallel/2lock.json

@@ -1,10 +1,6 @@
 {
     "builders": [
         {"type": "lock", "name": "build0"},
-        {"type": "parallel-test", "name": "build1"},
+        {"type": "lock", "name": "build1"}
-        {"type": "parallel-test", "name": "build2"},
-        {"type": "lock", "name": "build3"},
-        {"type": "parallel-test", "name": "build4"},
-        {"type": "parallel-test", "name": "build5"}
     ]
 }