package assert
import (
"fmt"
"go/ast"
"gotest.tools/assert/cmp"
"gotest.tools/internal/format"
"gotest.tools/internal/source"
)
func runComparison(
t TestingT,
argSelector argSelector,
f cmp.Comparison,
msgAndArgs ...interface{},
) bool {
if ht, ok := t.(helperT); ok {
ht.Helper()
}
result := f()
if result.Success() {
return true
}
var message string
switch typed := result.(type) {
case resultWithComparisonArgs:
const stackIndex = 3 // Assert/Check, assert, runComparison
args, err := source.CallExprArgs(stackIndex)
if err != nil {
t.Log(err.Error())
}
message = typed.FailureMessage(filterPrintableExpr(argSelector(args)))
case resultBasic:
message = typed.FailureMessage()
default:
message = fmt.Sprintf("comparison returned invalid Result type: %T", result)
}
t.Log(format.WithCustomMessage(failureMessage+message, msgAndArgs...))
return false
}
type resultWithComparisonArgs interface {
FailureMessage(args []ast.Expr) string
}
type resultBasic interface {
FailureMessage() string
}
// filterPrintableExpr filters the ast.Expr slice to only include Expr that are
// easy to read when printed and contain relevant information to an assertion.
//
// Ident and SelectorExpr are included because they print nicely and the variable
// names may provide additional context to their values.
// BasicLit and CompositeLit are excluded because their source is equivalent to
// their value, which is already available.
// Other types are ignored for now, but could be added if they are relevant.
func filterPrintableExpr(args []ast.Expr) []ast.Expr {
result := make([]ast.Expr, len(args))
for i, arg := range args {
if isShortPrintableExpr(arg) {
result[i] = arg
continue
}
if starExpr, ok := arg.(*ast.StarExpr); ok {
result[i] = starExpr.X
continue
}
result[i] = nil
}
return result
}
func isShortPrintableExpr(expr ast.Expr) bool {
switch expr.(type) {
case *ast.Ident, *ast.SelectorExpr, *ast.IndexExpr, *ast.SliceExpr:
return true
case *ast.BinaryExpr, *ast.UnaryExpr:
return true
default:
// CallExpr, ParenExpr, TypeAssertExpr, KeyValueExpr, StarExpr
return false
}
}
type argSelector func([]ast.Expr) []ast.Expr
func argsAfterT(args []ast.Expr) []ast.Expr {
if len(args) < 1 {
return nil
}
return args[1:]
}
func argsFromComparisonCall(args []ast.Expr) []ast.Expr {
if len(args) < 1 {
return nil
}
if callExpr, ok := args[1].(*ast.CallExpr); ok {
return callExpr.Args
}
return nil
}
