[BEAM-9951] Wrapping up synthetic integration tests.

Adding testing, and adjusting the error message for the count transform.

sdks/go/pkg/beam/testing/passert/count.go

@@ -20,16 +20,18 @@ import (
 
  "github.com/apache/beam/sdks/go/pkg/beam"
  "github.com/apache/beam/sdks/go/pkg/beam/core/typex"
+ "github.com/apache/beam/sdks/go/pkg/beam/internal/errors"
 )
 
+// Count verifies the given PCollection<T> has the specified number of elements.
 func Count(s beam.Scope, col beam.PCollection, name string, count int) {
  s = s.Scope(fmt.Sprintf("passert.Count(%v)", name))
 
  if typex.IsKV(col.Type()) {
  col = beam.DropKey(s, col)
  }
  counted := beam.Combine(s, &elmCountCombineFn{}, col)
- Equals(s, counted, count)
+ beam.ParDo0(s, &errFn{Name: name, Count: count}, counted)
 }
 
 type elmCountCombineFn struct {
@@ -50,3 +52,15 @@ func (f *elmCountCombineFn) MergeAccumulators(a, b int) int {
 func (f *elmCountCombineFn) ExtractOutput(a int) int {
  return a
 }
+
+type errFn struct {
+ Name string `json:"name,omitempty"`
+ Count int `json:"count,omitempty"`
+}
+
+func (f *errFn) ProcessElement(count int) error {
+ if f.Count != count {
+ return errors.Errorf("passert.Count(%v) = %v, want %v", f.Name, count, f.Count)
+ }
+ return nil
+}

sdks/go/pkg/beam/testing/passert/count_test.go

@@ -0,0 +1,45 @@
+// 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
+//
+// https://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 passert
+
+import (
+ "testing"
+
+ "github.com/apache/beam/sdks/go/pkg/beam"
+ "github.com/apache/beam/sdks/go/pkg/beam/testing/ptest"
+)
+
+func TestCount_Good(t *testing.T) {
+ p, s := beam.NewPipelineWithRoot()
+ col := beam.Create(s, "a", "b", "c", "d", "e")
+ count := 5
+
+ Count(s, col, "TestCount_Good", count)
+ if err := ptest.Run(p); err != nil {
+ t.Errorf("Pipeline failed: %v", err)
+ }
+}
+
+func TestCount_Bad(t *testing.T) {
+ p, s := beam.NewPipelineWithRoot()
+ col := beam.Create(s, "a", "b", "c", "d", "e")
+ count := 10
+
+ Count(s, col, "TestCount_Bad", count)
+ if err := ptest.Run(p); err == nil {
+ t.Errorf("pipeline SUCCEEDED but should have failed")
+ }
+}

sdks/go/pkg/beam/testing/passert/passert.go

@@ -29,7 +29,7 @@ import (
 )
 
 //go:generate go install github.com/apache/beam/sdks/go/cmd/starcgen
-//go:generate starcgen --package=passert --identifiers=diffFn,failFn,failIfBadEntries,failKVFn,failGBKFn,hashFn,sumFn,elmCountCombineFn
+//go:generate starcgen --package=passert --identifiers=diffFn,failFn,failIfBadEntries,failKVFn,failGBKFn,hashFn,sumFn,errFn,elmCountCombineFn
 //go:generate go fmt
 
 // Diff splits 2 incoming PCollections into 3: left only, both, right only. Duplicates are