Merge pull request #103 from steffnova/feature/issues/102

🤖[feature/issues/102] Add tests for Array shrinker

shrinker/array.go

@@ -1,11 +1,17 @@
 package shrinker
 
 import (
+	"fmt"
+
 	"github.com/steffnova/go-check/arbitrary"
 )
 
 func Array(original arbitrary.Arbitrary, shrinkers []Shrinker) Shrinker {
 	switch {
+	case original.Value.Len() != len(original.Elements):
+		return Fail(fmt.Errorf("Invalid number of elements. Expected: %d", len(original.Elements)))
+	case len(original.Elements) != len(shrinkers):
+		return Fail(fmt.Errorf("Number of shrinkers: %d must match number of elements: %d", len(shrinkers), len(original.Elements)))
 	default:
 		return Chain(
 			CollectionElement(shrinkers...),

shrinker/array_test.go

@@ -0,0 +1,72 @@
+package shrinker
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/steffnova/go-check/arbitrary"
+	"github.com/steffnova/go-check/constraints"
+)
+
+func TestArray(t *testing.T) {
+
+	testCases := map[string]func(t *testing.T){
+		"InvalidOriginal": func(t *testing.T) {
+			arr := [10]uint64{1, 2, 3, 4, 5, 6, 7, 8, 9}
+			arb := arbitrary.Arbitrary{Value: reflect.ValueOf(arr)}
+			shrinker := Array(arb, nil)
+			if _, _, err := shrinker(arbitrary.Arbitrary{}, true); err == nil {
+				t.Fatalf("Expected error when original arbitrary is invalid")
+			}
+		},
+		"InvalidShrinkers": func(t *testing.T) {
+			arr := [10]uint64{1, 2, 3, 4, 5, 6, 7, 8, 9}
+			elements := make([]arbitrary.Arbitrary, len(arr))
+			for index, arr := range arr {
+				elements[index] = arbitrary.Arbitrary{Value: reflect.ValueOf(arr)}
+			}
+			arb := arbitrary.Arbitrary{Value: reflect.ValueOf(arr), Elements: elements}
+			shrinker := Array(arb, []Shrinker{})
+			if _, _, err := shrinker(arb, true); err == nil {
+				t.Fatalf("Expected error when original arbitrary is invalid")
+			}
+		},
+		"ErrorWhenArbitraryIsNotArray": func(t *testing.T) {
+			arr := [10]uint64{1, 2, 3, 4, 5, 6, 7, 8, 9}
+			arb := arbitrary.Arbitrary{Value: reflect.ValueOf(arr)}
+			shrinker := Array(arb, nil)
+			if _, _, err := shrinker(arbitrary.Arbitrary{}, true); err == nil {
+				t.Fatalf("Expected error when passed arbitrary is not a array")
+			}
+		},
+		"ShrinkingFinishes": func(t *testing.T) {
+			arr := [10]uint64{1, 2, 3, 4, 5, 6, 7, 8, 9}
+			elements := make([]arbitrary.Arbitrary, len(arr))
+			shrinkers := make([]Shrinker, len(arr))
+
+			for index, arr := range arr {
+				elements[index] = arbitrary.Arbitrary{Value: reflect.ValueOf(arr)}
+				shrinkers[index] = Uint64(constraints.Uint64Default())
+			}
+
+			arb := arbitrary.Arbitrary{Value: reflect.ValueOf(arr), Elements: elements}
+			shrinker := Array(arb, shrinkers)
+
+			for shrinker != nil {
+				var err error
+				arb, shrinker, err = shrinker(arb, true)
+				if err != nil {
+					t.Fatalf("Unexpected error: %s", err)
+				}
+			}
+
+			if arb.Value.Interface().([10]uint64) != [10]uint64{0, 0, 0, 0, 0, 0, 0, 0, 0} {
+				t.Fatalf("Shrinking failed")
+			}
+		},
+	}
+
+	for name, testCase := range testCases {
+		t.Run(name, testCase)
+	}
+}