From 3d860530a904004aea5bc95e6331b3b11cec1877 Mon Sep 17 00:00:00 2001 From: Eyal Soha Date: Fri, 24 Apr 2020 15:02:33 -0700 Subject: Better error message from ExpectFrame Display the errors as diffs between the expected and wanted frame. PiperOrigin-RevId: 308333271 --- test/packetimpact/testbench/layers.go | 245 ++++++++++++++++++++++++++++++++++ 1 file changed, 245 insertions(+) (limited to 'test/packetimpact/testbench/layers.go') diff --git a/test/packetimpact/testbench/layers.go b/test/packetimpact/testbench/layers.go index 01e99567d..2cbbbb318 100644 --- a/test/packetimpact/testbench/layers.go +++ b/test/packetimpact/testbench/layers.go @@ -22,6 +22,7 @@ import ( "github.com/google/go-cmp/cmp" "github.com/google/go-cmp/cmp/cmpopts" + "go.uber.org/multierr" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/tcpip/header" @@ -720,3 +721,247 @@ func (ls *Layers) match(other Layers) bool { } return true } + +// layerDiff stores the diffs for each field along with the label for the Layer. +// If rows is nil, that means that there was no diff. +type layerDiff struct { + label string + rows []layerDiffRow +} + +// layerDiffRow stores the fields and corresponding values for two got and want +// layers. If the value was nil then the string stored is the empty string. +type layerDiffRow struct { + field, got, want string +} + +// diffLayer extracts all differing fields between two layers. +func diffLayer(got, want Layer) []layerDiffRow { + vGot := reflect.ValueOf(got).Elem() + vWant := reflect.ValueOf(want).Elem() + if vGot.Type() != vWant.Type() { + return nil + } + t := vGot.Type() + var result []layerDiffRow + for i := 0; i < t.NumField(); i++ { + t := t.Field(i) + if t.Anonymous { + // Ignore the LayerBase in the Layer struct. + continue + } + vGot := vGot.Field(i) + vWant := vWant.Field(i) + gotString := "" + if !vGot.IsNil() { + gotString = fmt.Sprint(reflect.Indirect(vGot)) + } + wantString := "" + if !vWant.IsNil() { + wantString = fmt.Sprint(reflect.Indirect(vWant)) + } + result = append(result, layerDiffRow{t.Name, gotString, wantString}) + } + return result +} + +// layerType returns a concise string describing the type of the Layer, like +// "TCP", or "IPv6". +func layerType(l Layer) string { + return reflect.TypeOf(l).Elem().Name() +} + +// diff compares Layers and returns a representation of the difference. Each +// Layer in the Layers is pairwise compared. If an element in either is nil, it +// is considered a match with the other Layer. If two Layers have differing +// types, they don't match regardless of the contents. If two Layers have the +// same type then the fields in the Layer are pairwise compared. Fields that are +// nil always match. Two non-nil fields only match if they point to equal +// values. diff returns an empty string if and only if *ls and other match. +func (ls *Layers) diff(other Layers) string { + var allDiffs []layerDiff + // Check the cases where one list is longer than the other, where one or both + // elements are nil, where the sides have different types, and where the sides + // have the same type. + for i := 0; i < len(*ls) || i < len(other); i++ { + if i >= len(*ls) { + // Matching ls against other where other is longer than ls. missing + // matches everything so we just include a label without any rows. Having + // no rows is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: "missing matches " + layerType(other[i]), + }) + continue + } + + if i >= len(other) { + // Matching ls against other where ls is longer than other. missing + // matches everything so we just include a label without any rows. Having + // no rows is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " matches missing", + }) + continue + } + + if (*ls)[i] == nil && other[i] == nil { + // Matching ls against other where both elements are nil. nil matches + // everything so we just include a label without any rows. Having no rows + // is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: "nil matches nil", + }) + continue + } + + if (*ls)[i] == nil { + // Matching ls against other where the element in ls is nil. nil matches + // everything so we just include a label without any rows. Having no rows + // is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: "nil matches " + layerType(other[i]), + }) + continue + } + + if other[i] == nil { + // Matching ls against other where the element in other is nil. nil + // matches everything so we just include a label without any rows. Having + // no rows is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " matches nil", + }) + continue + } + + if reflect.TypeOf((*ls)[i]) == reflect.TypeOf(other[i]) { + // Matching ls against other where both elements have the same type. Match + // each field pairwise and only report a diff if there is a mismatch, + // which is only when both sides are non-nil and have differring values. + diff := diffLayer((*ls)[i], other[i]) + var layerDiffRows []layerDiffRow + for _, d := range diff { + if d.got == "" || d.want == "" || d.got == d.want { + continue + } + layerDiffRows = append(layerDiffRows, layerDiffRow{ + d.field, + d.got, + d.want, + }) + } + if len(layerDiffRows) > 0 { + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]), + rows: layerDiffRows, + }) + } else { + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " matches " + layerType(other[i]), + // Having no rows is a sign that there was no diff. + }) + } + continue + } + // Neither side is nil and the types are different, so we'll display one + // side then the other. + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " doesn't match " + layerType(other[i]), + }) + diff := diffLayer((*ls)[i], (*ls)[i]) + layerDiffRows := []layerDiffRow{} + for _, d := range diff { + if len(d.got) == 0 { + continue + } + layerDiffRows = append(layerDiffRows, layerDiffRow{ + d.field, + d.got, + "", + }) + } + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]), + rows: layerDiffRows, + }) + + layerDiffRows = []layerDiffRow{} + diff = diffLayer(other[i], other[i]) + for _, d := range diff { + if len(d.want) == 0 { + continue + } + layerDiffRows = append(layerDiffRows, layerDiffRow{ + d.field, + "", + d.want, + }) + } + allDiffs = append(allDiffs, layerDiff{ + label: layerType(other[i]), + rows: layerDiffRows, + }) + } + + output := "" + // These are for output formatting. + maxLabelLen, maxFieldLen, maxGotLen, maxWantLen := 0, 0, 0, 0 + foundOne := false + for _, l := range allDiffs { + if len(l.label) > maxLabelLen && len(l.rows) > 0 { + maxLabelLen = len(l.label) + } + if l.rows != nil { + foundOne = true + } + for _, r := range l.rows { + if len(r.field) > maxFieldLen { + maxFieldLen = len(r.field) + } + if l := len(fmt.Sprint(r.got)); l > maxGotLen { + maxGotLen = l + } + if l := len(fmt.Sprint(r.want)); l > maxWantLen { + maxWantLen = l + } + } + } + if !foundOne { + return "" + } + for _, l := range allDiffs { + if len(l.rows) == 0 { + output += "(" + l.label + ")\n" + continue + } + for i, r := range l.rows { + var label string + if i == 0 { + label = l.label + ":" + } + output += fmt.Sprintf( + "%*s %*s %*v %*v\n", + maxLabelLen+1, label, + maxFieldLen+1, r.field+":", + maxGotLen, r.got, + maxWantLen, r.want, + ) + } + } + return output +} + +// merge merges the other Layers into ls. If the other Layers is longer, those +// additional Layer structs are added to ls. The errors from merging are +// collected and returned. +func (ls *Layers) merge(other Layers) error { + var errs error + for i, o := range other { + if i < len(*ls) { + errs = multierr.Combine(errs, (*ls)[i].merge(o)) + } else { + *ls = append(*ls, o) + } + } + return errs +} -- cgit v1.2.3