[GitHub] [beam] johannaojeling commented on a diff in pull request #25565: [prism] Add in element manager

["johannaojeling (via GitHub)" <gi...@apache.org>]

johannaojeling commented on code in PR #25565:
URL: https://github.com/apache/beam/pull/25565#discussion_r1112334964


##########
sdks/go/pkg/beam/runners/prism/internal/engine/elementmanager_test.go:
##########
@@ -0,0 +1,516 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package engine
+
+import (
+	"container/heap"
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/coder"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/mtime"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/runtime/exec"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/typex"
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestElementHeap(t *testing.T) {
+	elements := elementHeap{
+		element{timestamp: mtime.EndOfGlobalWindowTime},
+		element{timestamp: mtime.MaxTimestamp},
+		element{timestamp: 3},
+		element{timestamp: mtime.MinTimestamp},
+		element{timestamp: 2},
+		element{timestamp: mtime.ZeroTimestamp},
+		element{timestamp: 1},
+	}
+	heap.Init(&elements)
+	heap.Push(&elements, element{timestamp: 4})
+
+	if got, want := elements.Len(), len(elements); got != want {
+		t.Errorf("elements.Len() = %v, want %v", got, want)
+	}
+	if got, want := elements[0].timestamp, mtime.MinTimestamp; got != want {
+		t.Errorf("elements[0].timestamp = %v, want %v", got, want)
+	}
+
+	wanted := []mtime.Time{mtime.MinTimestamp, mtime.ZeroTimestamp, 1, 2, 3, 4, mtime.EndOfGlobalWindowTime, mtime.MaxTimestamp}
+	for i, want := range wanted {
+		if got := heap.Pop(&elements).(element).timestamp; got != want {
+			t.Errorf("[%d] heap.Pop(&elements).(element).timestamp = %v, want %v", i, got, want)
+		}
+	}
+}
+
+func TestStageState_minPendingTimestamp(t *testing.T) {
+
+	newState := func() *stageState {
+		return makeStageState("test", []string{"testInput"}, nil, []string{"testOutput"})
+	}
+	t.Run("noElements", func(t *testing.T) {
+		ss := newState()
+		got := ss.minPendingTimestamp()
+		want := mtime.MaxTimestamp
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	want := mtime.ZeroTimestamp - 20
+	t.Run("onlyPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			element{timestamp: mtime.EndOfGlobalWindowTime},
+			element{timestamp: mtime.MaxTimestamp},
+			element{timestamp: 3},
+			element{timestamp: want},
+			element{timestamp: 2},
+			element{timestamp: mtime.ZeroTimestamp},
+			element{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("onlyInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"b": {
+				es: []element{
+					{timestamp: 3},
+					{timestamp: want},
+					{timestamp: 2},
+					{timestamp: 1},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("minInPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: want},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+	t.Run("minInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: want},
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+}
+
+func TestStageState_getUpstreamWatermark(t *testing.T) {

Review Comment:
   ```suggestion
   func TestStageState_UpstreamWatermark(t *testing.T) {
   ```



##########
sdks/go/pkg/beam/runners/prism/internal/engine/elementmanager_test.go:
##########
@@ -0,0 +1,516 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package engine
+
+import (
+	"container/heap"
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/coder"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/mtime"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/runtime/exec"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/typex"
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestElementHeap(t *testing.T) {
+	elements := elementHeap{
+		element{timestamp: mtime.EndOfGlobalWindowTime},
+		element{timestamp: mtime.MaxTimestamp},
+		element{timestamp: 3},
+		element{timestamp: mtime.MinTimestamp},
+		element{timestamp: 2},
+		element{timestamp: mtime.ZeroTimestamp},
+		element{timestamp: 1},
+	}
+	heap.Init(&elements)
+	heap.Push(&elements, element{timestamp: 4})
+
+	if got, want := elements.Len(), len(elements); got != want {
+		t.Errorf("elements.Len() = %v, want %v", got, want)
+	}
+	if got, want := elements[0].timestamp, mtime.MinTimestamp; got != want {
+		t.Errorf("elements[0].timestamp = %v, want %v", got, want)
+	}
+
+	wanted := []mtime.Time{mtime.MinTimestamp, mtime.ZeroTimestamp, 1, 2, 3, 4, mtime.EndOfGlobalWindowTime, mtime.MaxTimestamp}
+	for i, want := range wanted {
+		if got := heap.Pop(&elements).(element).timestamp; got != want {
+			t.Errorf("[%d] heap.Pop(&elements).(element).timestamp = %v, want %v", i, got, want)
+		}
+	}
+}
+
+func TestStageState_minPendingTimestamp(t *testing.T) {
+
+	newState := func() *stageState {
+		return makeStageState("test", []string{"testInput"}, nil, []string{"testOutput"})
+	}
+	t.Run("noElements", func(t *testing.T) {
+		ss := newState()
+		got := ss.minPendingTimestamp()
+		want := mtime.MaxTimestamp
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	want := mtime.ZeroTimestamp - 20
+	t.Run("onlyPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			element{timestamp: mtime.EndOfGlobalWindowTime},
+			element{timestamp: mtime.MaxTimestamp},
+			element{timestamp: 3},
+			element{timestamp: want},
+			element{timestamp: 2},
+			element{timestamp: mtime.ZeroTimestamp},
+			element{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("onlyInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"b": {
+				es: []element{
+					{timestamp: 3},
+					{timestamp: want},
+					{timestamp: 2},
+					{timestamp: 1},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("minInPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: want},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+	t.Run("minInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: want},
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+}
+
+func TestStageState_getUpstreamWatermark(t *testing.T) {
+	impulse := makeStageState("impulse", nil, nil, []string{"output"})
+	_, up := impulse.UpstreamWatermark()
+	if got, want := up, mtime.MaxTimestamp; got != want {
+		t.Errorf("impulse.getUpstreamWatermark() = %v, want %v", got, want)
+	}
+
+	dofn := makeStageState("dofn", []string{"input"}, nil, []string{"output"})
+	dofn.updateUpstreamWatermark("input", 42)
+
+	_, up = dofn.UpstreamWatermark()
+	if got, want := up, mtime.Time(42); got != want {
+		t.Errorf("dofn.getUpstreamWatermark() = %v, want %v", got, want)

Review Comment:
   ```suggestion
   		t.Errorf("dofn.UpstreamWatermark() = %v, want %v", got, want)
   ```



##########
sdks/go/pkg/beam/runners/prism/internal/engine/elementmanager_test.go:
##########
@@ -0,0 +1,516 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package engine
+
+import (
+	"container/heap"
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/coder"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/mtime"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/runtime/exec"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/typex"
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestElementHeap(t *testing.T) {
+	elements := elementHeap{
+		element{timestamp: mtime.EndOfGlobalWindowTime},
+		element{timestamp: mtime.MaxTimestamp},
+		element{timestamp: 3},
+		element{timestamp: mtime.MinTimestamp},
+		element{timestamp: 2},
+		element{timestamp: mtime.ZeroTimestamp},
+		element{timestamp: 1},
+	}
+	heap.Init(&elements)
+	heap.Push(&elements, element{timestamp: 4})
+
+	if got, want := elements.Len(), len(elements); got != want {
+		t.Errorf("elements.Len() = %v, want %v", got, want)
+	}
+	if got, want := elements[0].timestamp, mtime.MinTimestamp; got != want {
+		t.Errorf("elements[0].timestamp = %v, want %v", got, want)
+	}
+
+	wanted := []mtime.Time{mtime.MinTimestamp, mtime.ZeroTimestamp, 1, 2, 3, 4, mtime.EndOfGlobalWindowTime, mtime.MaxTimestamp}
+	for i, want := range wanted {
+		if got := heap.Pop(&elements).(element).timestamp; got != want {
+			t.Errorf("[%d] heap.Pop(&elements).(element).timestamp = %v, want %v", i, got, want)
+		}
+	}
+}
+
+func TestStageState_minPendingTimestamp(t *testing.T) {
+
+	newState := func() *stageState {
+		return makeStageState("test", []string{"testInput"}, nil, []string{"testOutput"})
+	}
+	t.Run("noElements", func(t *testing.T) {
+		ss := newState()
+		got := ss.minPendingTimestamp()
+		want := mtime.MaxTimestamp
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	want := mtime.ZeroTimestamp - 20
+	t.Run("onlyPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			element{timestamp: mtime.EndOfGlobalWindowTime},
+			element{timestamp: mtime.MaxTimestamp},
+			element{timestamp: 3},
+			element{timestamp: want},
+			element{timestamp: 2},
+			element{timestamp: mtime.ZeroTimestamp},
+			element{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("onlyInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"b": {
+				es: []element{
+					{timestamp: 3},
+					{timestamp: want},
+					{timestamp: 2},
+					{timestamp: 1},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("minInPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: want},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+	t.Run("minInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: want},
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+}
+
+func TestStageState_getUpstreamWatermark(t *testing.T) {
+	impulse := makeStageState("impulse", nil, nil, []string{"output"})
+	_, up := impulse.UpstreamWatermark()
+	if got, want := up, mtime.MaxTimestamp; got != want {
+		t.Errorf("impulse.getUpstreamWatermark() = %v, want %v", got, want)
+	}
+
+	dofn := makeStageState("dofn", []string{"input"}, nil, []string{"output"})
+	dofn.updateUpstreamWatermark("input", 42)
+
+	_, up = dofn.UpstreamWatermark()
+	if got, want := up, mtime.Time(42); got != want {
+		t.Errorf("dofn.getUpstreamWatermark() = %v, want %v", got, want)
+	}
+
+	flatten := makeStageState("flatten", []string{"a", "b", "c"}, nil, []string{"output"})
+	flatten.updateUpstreamWatermark("a", 50)
+	flatten.updateUpstreamWatermark("b", 42)
+	flatten.updateUpstreamWatermark("c", 101)
+	_, up = flatten.UpstreamWatermark()
+	if got, want := up, mtime.Time(42); got != want {
+		t.Errorf("flatten.getUpstreamWatermark() = %v, want %v", got, want)

Review Comment:
   ```suggestion
   		t.Errorf("flatten.UpstreamWatermark() = %v, want %v", got, want)
   ```



##########
sdks/go/pkg/beam/runners/prism/internal/engine/elementmanager_test.go:
##########
@@ -0,0 +1,516 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package engine
+
+import (
+	"container/heap"
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/coder"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/mtime"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/runtime/exec"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/typex"
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestElementHeap(t *testing.T) {
+	elements := elementHeap{
+		element{timestamp: mtime.EndOfGlobalWindowTime},
+		element{timestamp: mtime.MaxTimestamp},
+		element{timestamp: 3},
+		element{timestamp: mtime.MinTimestamp},
+		element{timestamp: 2},
+		element{timestamp: mtime.ZeroTimestamp},
+		element{timestamp: 1},
+	}
+	heap.Init(&elements)
+	heap.Push(&elements, element{timestamp: 4})
+
+	if got, want := elements.Len(), len(elements); got != want {
+		t.Errorf("elements.Len() = %v, want %v", got, want)
+	}
+	if got, want := elements[0].timestamp, mtime.MinTimestamp; got != want {
+		t.Errorf("elements[0].timestamp = %v, want %v", got, want)
+	}
+
+	wanted := []mtime.Time{mtime.MinTimestamp, mtime.ZeroTimestamp, 1, 2, 3, 4, mtime.EndOfGlobalWindowTime, mtime.MaxTimestamp}
+	for i, want := range wanted {
+		if got := heap.Pop(&elements).(element).timestamp; got != want {
+			t.Errorf("[%d] heap.Pop(&elements).(element).timestamp = %v, want %v", i, got, want)
+		}
+	}
+}
+
+func TestStageState_minPendingTimestamp(t *testing.T) {
+
+	newState := func() *stageState {
+		return makeStageState("test", []string{"testInput"}, nil, []string{"testOutput"})
+	}
+	t.Run("noElements", func(t *testing.T) {
+		ss := newState()
+		got := ss.minPendingTimestamp()
+		want := mtime.MaxTimestamp
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	want := mtime.ZeroTimestamp - 20
+	t.Run("onlyPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			element{timestamp: mtime.EndOfGlobalWindowTime},
+			element{timestamp: mtime.MaxTimestamp},
+			element{timestamp: 3},
+			element{timestamp: want},
+			element{timestamp: 2},
+			element{timestamp: mtime.ZeroTimestamp},
+			element{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("onlyInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"b": {
+				es: []element{
+					{timestamp: 3},
+					{timestamp: want},
+					{timestamp: 2},
+					{timestamp: 1},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("minInPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: want},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+	t.Run("minInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: want},
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+}
+
+func TestStageState_getUpstreamWatermark(t *testing.T) {
+	impulse := makeStageState("impulse", nil, nil, []string{"output"})
+	_, up := impulse.UpstreamWatermark()
+	if got, want := up, mtime.MaxTimestamp; got != want {
+		t.Errorf("impulse.getUpstreamWatermark() = %v, want %v", got, want)
+	}
+
+	dofn := makeStageState("dofn", []string{"input"}, nil, []string{"output"})
+	dofn.updateUpstreamWatermark("input", 42)
+
+	_, up = dofn.UpstreamWatermark()
+	if got, want := up, mtime.Time(42); got != want {
+		t.Errorf("dofn.getUpstreamWatermark() = %v, want %v", got, want)
+	}
+
+	flatten := makeStageState("flatten", []string{"a", "b", "c"}, nil, []string{"output"})
+	flatten.updateUpstreamWatermark("a", 50)
+	flatten.updateUpstreamWatermark("b", 42)
+	flatten.updateUpstreamWatermark("c", 101)
+	_, up = flatten.UpstreamWatermark()
+	if got, want := up, mtime.Time(42); got != want {
+		t.Errorf("flatten.getUpstreamWatermark() = %v, want %v", got, want)
+	}
+}
+
+func TestStageState_updateWatermarks(t *testing.T) {
+	inputCol := "testInput"
+	outputCol := "testOutput"
+	newState := func() (*stageState, *stageState, *ElementManager) {
+		underTest := makeStageState("underTest", []string{inputCol}, nil, []string{outputCol})
+		outStage := makeStageState("outStage", []string{outputCol}, nil, nil)
+		em := &ElementManager{
+			consumers: map[string][]string{
+				inputCol:  {underTest.ID},
+				outputCol: {outStage.ID},
+			},
+			stages: map[string]*stageState{
+				outStage.ID:  outStage,
+				underTest.ID: underTest,
+			},
+		}
+		return underTest, outStage, em
+	}
+
+	tests := []struct {
+		name                                  string
+		initInput, initOutput                 mtime.Time
+		upstream, minPending, minStateHold    mtime.Time
+		wantInput, wantOutput, wantDownstream mtime.Time
+	}{
+		{
+			name:           "initialized",
+			initInput:      mtime.MinTimestamp,
+			initOutput:     mtime.MinTimestamp,
+			upstream:       mtime.MinTimestamp,
+			minPending:     mtime.EndOfGlobalWindowTime,
+			minStateHold:   mtime.EndOfGlobalWindowTime,
+			wantInput:      mtime.MinTimestamp, // match default
+			wantOutput:     mtime.MinTimestamp, // match upstream
+			wantDownstream: mtime.MinTimestamp, // match upstream
+		}, {
+			name:           "upstream",
+			initInput:      mtime.MinTimestamp,
+			initOutput:     mtime.MinTimestamp,
+			upstream:       mtime.ZeroTimestamp,
+			minPending:     mtime.EndOfGlobalWindowTime,
+			minStateHold:   mtime.EndOfGlobalWindowTime,
+			wantInput:      mtime.ZeroTimestamp, // match upstream
+			wantOutput:     mtime.ZeroTimestamp, // match upstream
+			wantDownstream: mtime.ZeroTimestamp, // match upstream
+		}, {
+			name:           "useMinPending",
+			initInput:      mtime.MinTimestamp,
+			initOutput:     mtime.MinTimestamp,
+			upstream:       mtime.ZeroTimestamp,
+			minPending:     -20,
+			minStateHold:   mtime.EndOfGlobalWindowTime,
+			wantInput:      -20, // match minPending
+			wantOutput:     -20, // match minPending
+			wantDownstream: -20, // match minPending
+		}, {
+			name:           "useStateHold",
+			initInput:      mtime.MinTimestamp,
+			initOutput:     mtime.MinTimestamp,
+			upstream:       mtime.ZeroTimestamp,
+			minPending:     -20,
+			minStateHold:   -30,
+			wantInput:      -20, // match minPending
+			wantOutput:     -30, // match state hold
+			wantDownstream: -30, // match state hold
+		}, {
+			name:           "noAdvance",
+			initInput:      20,
+			initOutput:     30,
+			upstream:       mtime.MinTimestamp,
+			wantInput:      20,                 // match original input
+			wantOutput:     30,                 // match original output
+			wantDownstream: mtime.MinTimestamp, // not propagated
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ss, outStage, em := newState()
+			ss.input = test.initInput
+			ss.output = test.initOutput
+			ss.updateUpstreamWatermark(inputCol, test.upstream)
+			ss.updateWatermarks(test.minPending, test.minStateHold, em)
+			if got, want := ss.input, test.wantInput; got != want {
+				pcol, up := ss.UpstreamWatermark()
+				t.Errorf("ss.updateWatermarks(%v,%v); ss.input = %v, want %v (upstream %v %v)", test.minPending, test.minStateHold, got, want, pcol, up)
+			}
+			if got, want := ss.output, test.wantOutput; got != want {
+				pcol, up := ss.UpstreamWatermark()
+				t.Errorf("ss.updateWatermarks(%v,%v); ss.output = %v, want %v (upstream %v %v)", test.minPending, test.minStateHold, got, want, pcol, up)
+			}
+			_, up := outStage.UpstreamWatermark()
+			if got, want := up, test.wantDownstream; got != want {
+				t.Errorf("outStage.getUpstreamWatermark() = %v, want %v", got, want)

Review Comment:
   ```suggestion
   				t.Errorf("outStage.UpstreamWatermark() = %v, want %v", got, want)
   ```



##########
sdks/go/pkg/beam/runners/prism/internal/engine/elementmanager_test.go:
##########
@@ -0,0 +1,516 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package engine
+
+import (
+	"container/heap"
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/coder"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/mtime"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph/window"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/runtime/exec"
+	"github.com/apache/beam/sdks/v2/go/pkg/beam/core/typex"
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestElementHeap(t *testing.T) {
+	elements := elementHeap{
+		element{timestamp: mtime.EndOfGlobalWindowTime},
+		element{timestamp: mtime.MaxTimestamp},
+		element{timestamp: 3},
+		element{timestamp: mtime.MinTimestamp},
+		element{timestamp: 2},
+		element{timestamp: mtime.ZeroTimestamp},
+		element{timestamp: 1},
+	}
+	heap.Init(&elements)
+	heap.Push(&elements, element{timestamp: 4})
+
+	if got, want := elements.Len(), len(elements); got != want {
+		t.Errorf("elements.Len() = %v, want %v", got, want)
+	}
+	if got, want := elements[0].timestamp, mtime.MinTimestamp; got != want {
+		t.Errorf("elements[0].timestamp = %v, want %v", got, want)
+	}
+
+	wanted := []mtime.Time{mtime.MinTimestamp, mtime.ZeroTimestamp, 1, 2, 3, 4, mtime.EndOfGlobalWindowTime, mtime.MaxTimestamp}
+	for i, want := range wanted {
+		if got := heap.Pop(&elements).(element).timestamp; got != want {
+			t.Errorf("[%d] heap.Pop(&elements).(element).timestamp = %v, want %v", i, got, want)
+		}
+	}
+}
+
+func TestStageState_minPendingTimestamp(t *testing.T) {
+
+	newState := func() *stageState {
+		return makeStageState("test", []string{"testInput"}, nil, []string{"testOutput"})
+	}
+	t.Run("noElements", func(t *testing.T) {
+		ss := newState()
+		got := ss.minPendingTimestamp()
+		want := mtime.MaxTimestamp
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	want := mtime.ZeroTimestamp - 20
+	t.Run("onlyPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			element{timestamp: mtime.EndOfGlobalWindowTime},
+			element{timestamp: mtime.MaxTimestamp},
+			element{timestamp: 3},
+			element{timestamp: want},
+			element{timestamp: 2},
+			element{timestamp: mtime.ZeroTimestamp},
+			element{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("onlyInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"b": {
+				es: []element{
+					{timestamp: 3},
+					{timestamp: want},
+					{timestamp: 2},
+					{timestamp: 1},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+
+	t.Run("minInPending", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: want},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: mtime.EndOfGlobalWindowTime,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+	t.Run("minInProgress", func(t *testing.T) {
+		ss := newState()
+		ss.pending = elementHeap{
+			{timestamp: 3},
+			{timestamp: 2},
+			{timestamp: 1},
+		}
+		heap.Init(&ss.pending)
+		ss.inprogress = map[string]elements{
+			"a": {
+				es: []element{
+					{timestamp: want},
+					{timestamp: mtime.EndOfGlobalWindowTime},
+					{timestamp: mtime.MaxTimestamp},
+				},
+				minTimestamp: want,
+			},
+			"c": {
+				es: []element{
+					{timestamp: mtime.ZeroTimestamp},
+				},
+				minTimestamp: mtime.ZeroTimestamp,
+			},
+		}
+
+		got := ss.minPendingTimestamp()
+		if got != want {
+			t.Errorf("ss.minPendingTimestamp() = %v, want %v", got, want)
+		}
+	})
+}
+
+func TestStageState_getUpstreamWatermark(t *testing.T) {
+	impulse := makeStageState("impulse", nil, nil, []string{"output"})
+	_, up := impulse.UpstreamWatermark()
+	if got, want := up, mtime.MaxTimestamp; got != want {
+		t.Errorf("impulse.getUpstreamWatermark() = %v, want %v", got, want)

Review Comment:
   ```suggestion
   		t.Errorf("impulse.UpstreamWatermark() = %v, want %v", got, want)
   ```



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscribe@beam.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org