Adding ExpectKnownOutputValue state check (#266)

statecheck/expect_known_output_value.go

@@ -0,0 +1,92 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package statecheck
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+
+	tfjson "github.com/hashicorp/terraform-json"
+
+	"github.com/hashicorp/terraform-plugin-testing/knownvalue"
+	"github.com/hashicorp/terraform-plugin-testing/tfjsonpath"
+)
+
+// Resource State Check
+var _ StateCheck = expectKnownOutputValue{}
+
+type expectKnownOutputValue struct {
+	outputAddress string
+	knownValue    knownvalue.Check
+}
+
+// CheckState implements the state check logic.
+func (e expectKnownOutputValue) CheckState(ctx context.Context, req CheckStateRequest, resp *CheckStateResponse) {
+	var output *tfjson.StateOutput
+
+	if req.State == nil {
+		resp.Error = fmt.Errorf("state is nil")
+	}
+
+	if req.State.Values == nil {
+		resp.Error = fmt.Errorf("state does not contain any state values")
+	}
+
+	for address, oc := range req.State.Values.Outputs {
+		if e.outputAddress == address {
+			output = oc
+
+			break
+		}
+	}
+
+	if output == nil {
+		resp.Error = fmt.Errorf("%s - Output not found in state", e.outputAddress)
+
+		return
+	}
+
+	result, err := tfjsonpath.Traverse(output.Value, tfjsonpath.Path{})
+
+	if err != nil {
+		resp.Error = err
+
+		return
+	}
+
+	if result == nil {
+		resp.Error = fmt.Errorf("value is null")
+
+		return
+	}
+
+	switch reflect.TypeOf(result).Kind() {
+	case reflect.Bool,
+		reflect.Map,
+		reflect.Slice,
+		reflect.String:
+		if err := e.knownValue.CheckValue(result); err != nil {
+			resp.Error = err
+
+			return
+		}
+	default:
+		errorStr := fmt.Sprintf("unrecognised output type: %T, known value type is %T", result, e.knownValue)
+		errorStr += "\n\nThis is an error in statecheck.ExpectKnownOutputValue.\nPlease report this to the maintainers."
+
+		resp.Error = fmt.Errorf(errorStr)
+
+		return
+	}
+}
+
+// ExpectKnownOutputValue returns a state check that asserts that the specified value
+// has a known type, and value.
+func ExpectKnownOutputValue(outputAddress string, knownValue knownvalue.Check) StateCheck {
+	return expectKnownOutputValue{
+		outputAddress: outputAddress,
+		knownValue:    knownValue,
+	}
+}