Added search.Expects and search.AssignUnique methods + tests

.github/coverage/cover.txt

@@ -98,23 +98,25 @@ github.com/0xrawsec/sod/schema.go:197:		update			100.0%
 github.com/0xrawsec/sod/schema.go:209:		mustCache		100.0%
 github.com/0xrawsec/sod/schema.go:213:		asyncWritesEnabled	100.0%
 github.com/0xrawsec/sod/schema.go:220:		control			80.0%
-github.com/0xrawsec/sod/search.go:15:		IsNoObjectFound		100.0%
-github.com/0xrawsec/sod/search.go:30:		newSearch		100.0%
-github.com/0xrawsec/sod/search.go:36:		Operation		66.7%
-github.com/0xrawsec/sod/search.go:50:		And			100.0%
-github.com/0xrawsec/sod/search.go:58:		Or			100.0%
-github.com/0xrawsec/sod/search.go:78:		Len			100.0%
-github.com/0xrawsec/sod/search.go:84:		Iterator		85.7%
-github.com/0xrawsec/sod/search.go:102:		Delete			75.0%
-github.com/0xrawsec/sod/search.go:113:		Reverse			100.0%
-github.com/0xrawsec/sod/search.go:119:		Limit			100.0%
-github.com/0xrawsec/sod/search.go:126:		One			100.0%
-github.com/0xrawsec/sod/search.go:137:		AssignOne		100.0%
-github.com/0xrawsec/sod/search.go:156:		Assign			100.0%
-github.com/0xrawsec/sod/search.go:175:		Collect			100.0%
-github.com/0xrawsec/sod/search.go:183:		Err			100.0%
-github.com/0xrawsec/sod/search.go:189:		one			91.7%
-github.com/0xrawsec/sod/search.go:211:		collect			93.3%
+github.com/0xrawsec/sod/search.go:16:		IsNoObjectFound		100.0%
+github.com/0xrawsec/sod/search.go:31:		newSearch		100.0%
+github.com/0xrawsec/sod/search.go:38:		Expects			83.3%
+github.com/0xrawsec/sod/search.go:54:		Operation		62.5%
+github.com/0xrawsec/sod/search.go:74:		And			100.0%
+github.com/0xrawsec/sod/search.go:83:		Or			90.0%
+github.com/0xrawsec/sod/search.go:105:		Len			100.0%
+github.com/0xrawsec/sod/search.go:111:		Iterator		77.8%
+github.com/0xrawsec/sod/search.go:133:		Delete			75.0%
+github.com/0xrawsec/sod/search.go:144:		Reverse			100.0%
+github.com/0xrawsec/sod/search.go:150:		Limit			100.0%
+github.com/0xrawsec/sod/search.go:157:		One			100.0%
+github.com/0xrawsec/sod/search.go:167:		AssignUnique		100.0%
+github.com/0xrawsec/sod/search.go:176:		AssignOne		100.0%
+github.com/0xrawsec/sod/search.go:195:		Assign			100.0%
+github.com/0xrawsec/sod/search.go:214:		Collect			100.0%
+github.com/0xrawsec/sod/search.go:222:		Err			100.0%
+github.com/0xrawsec/sod/search.go:228:		one			91.7%
+github.com/0xrawsec/sod/search.go:250:		collect			93.3%
 github.com/0xrawsec/sod/sod.go:31:		newObjectMap		100.0%
 github.com/0xrawsec/sod/sod.go:35:		put			100.0%
 github.com/0xrawsec/sod/sod.go:41:		get			100.0%
@@ -198,4 +200,4 @@ github.com/0xrawsec/sod/utils.go:197:		dbgLock			0.0%
 github.com/0xrawsec/sod/utils.go:206:		fieldPath		100.0%
 github.com/0xrawsec/sod/utils.go:210:		unmarshalJsonFile	80.0%
 github.com/0xrawsec/sod/utils.go:238:		writeReader		60.0%
-total:						(statements)		88.7%
+total:						(statements)		88.4%

search.go

@@ -8,8 +8,9 @@ import (
 )
 
 var (
-	ErrUnknownOperator = errors.New("unknown logical operator")
-	ErrNoObjectFound   = errors.New("no object found")
+	ErrUnknownOperator           = errors.New("unknown logical operator")
+	ErrNoObjectFound             = errors.New("no object found")
+	ErrUnexpectedNumberOfResults = errors.New("unexpected number of results")
 )
 
 func IsNoObjectFound(err error) bool {
@@ -31,10 +32,33 @@ func newSearch(db *DB, o Object, f []*indexedField, err error) *Search {
 	return &Search{db: db, object: o, fields: f, limit: math.MaxUint, err: err}
 }
 
+// Expects checks that the number of results is the one expected
+// if not, next call to s.Err must return an error and any subsbequent
+// attempt to collect results must fail
+func (s *Search) Expects(n int) *Search {
+	found := len(s.fields)
+
+	if s.err != nil {
+		return s
+	}
+
+	if found != n {
+		s.err = fmt.Errorf("%w expected %d, found %d", ErrUnexpectedNumberOfResults, n, found)
+	}
+
+	return s
+}
+
 // Operation performs a new Search while ANDing or ORing the results
 // operator must be in ["and", "&&", "or", "||"]
 func (s *Search) Operation(operator, field, comparator string, value interface{}) *Search {
+
 	op := strings.ToLower(operator)
+
+	if s.err != nil {
+		return s
+	}
+
 	switch op {
 	case "and", "&&":
 		return s.And(field, comparator, value)
@@ -48,17 +72,20 @@ func (s *Search) Operation(operator, field, comparator string, value interface{}
 
 // And performs a new Search while "ANDing" search results
 func (s *Search) And(field, operator string, value interface{}) *Search {
-	if s.Err() != nil {
+	if s.err != nil {
 		return s
 	}
+
 	return s.db.search(s.object, field, operator, value, s.fields)
 }
 
 // Or performs a new Search while "ORing" search results
 func (s *Search) Or(field, operator string, value interface{}) *Search {
-	if s.Err() != nil {
+
+	if s.err != nil {
 		return s
 	}
+
 	new := s.db.search(s.object, field, operator, value, nil)
 	marked := make(map[uint64]bool)
 	// we mark the fields of the new search
@@ -84,6 +111,10 @@ func (s *Search) Len() int {
 func (s *Search) Iterator() (it *iterator, err error) {
 	var sch *Schema
 
+	if s.err != nil {
+		return nil, s.err
+	}
+
 	if sch, err = s.db.schema(s.object); err != nil {
 		return
 	}
@@ -130,6 +161,14 @@ func (s *Search) One() (o Object, err error) {
 	return s.one()
 }
 
+// AssignUnique checks there is only one result in search and assign it
+// to target. If search retuns more than one result, ErrUnexpectedNumberOfResults
+// is returned
+func (s *Search) AssignUnique(target interface{}) (err error) {
+	s.Expects(1)
+	return s.AssignOne(target)
+}
+
 // AssignOne returns the first result found calling Collect function
 // and assign the Object found to target. Target must be a *sod.Object
 // otherwise the function panics. If no Object is found, ErrNoObjectFound
@@ -212,8 +251,8 @@ func (s *Search) collect() (out []Object, err error) {
 	var it *iterator
 	var o Object
 
-	if s.Err() != nil {
-		return nil, s.Err()
+	if s.err != nil {
+		return nil, s.err
 	}
 
 	if it, err = s.Iterator(); err != nil {

sod_test.go

@@ -679,7 +679,9 @@ func TestUniqueObject(t *testing.T) {
 	tt.ExpectErr(db.InsertOrUpdate(&testStructUnique{A: 42}), ErrFieldUnique)
 
 	tt.ShouldPanic(func() { db.Search(&testStructUnique{}, "A", "=", 42).AssignOne(nil) })
-	tt.CheckErr(db.Search(&testStructUnique{}, "A", "=", 42).AssignOne(&uninit))
+	tt.ExpectErr(db.Search(&testStructUnique{}, "A", "=", 42).Expects(2).AssignOne(&uninit), ErrUnexpectedNumberOfResults)
+	tt.CheckErr(db.Search(&testStructUnique{}, "A", "=", 42).Expects(1).AssignOne(&uninit))
+	tt.CheckErr(db.Search(&testStructUnique{}, "A", "=", 42).AssignUnique(&uninit))
 	tt.Assert(uninit.A == 42)
 
 	ts := &testStructUnique{}