Report argument mismatch details when no expectation matches by arguments

sqlmock_before_go18.go

@@ -51,6 +51,7 @@ func (c *sqlmock) query(query string, args []namedValue) (*ExpectedQuery, error)
 	var expected *ExpectedQuery
 	var fulfilled int
 	var ok bool
+	var argMismatch error
 	for _, next := range c.expected {
 		next.Lock()
 		if next.fulfilled() {
@@ -74,6 +75,10 @@ func (c *sqlmock) query(query string, args []namedValue) (*ExpectedQuery, error)
 			if err := qr.attemptArgMatch(args); err == nil {
 				expected = qr
 				break
+			} else {
+				// remember the reason the sql matched but the args did not,
+				// so it can be reported if no other expectation matches
+				argMismatch = err
 			}
 		}
 		next.Unlock()
@@ -84,7 +89,11 @@ func (c *sqlmock) query(query string, args []namedValue) (*ExpectedQuery, error)
 		if fulfilled == len(c.expected) {
 			msg = "all expectations were already fulfilled, " + msg
 		}
-		return nil, fmt.Errorf(msg, query, args)
+		err := fmt.Errorf(msg, query, args)
+		if argMismatch != nil {
+			err = fmt.Errorf("%s, arguments do not match: %s", err, argMismatch)
+		}
+		return nil, err
 	}
 
 	defer expected.Unlock()
@@ -133,6 +142,7 @@ func (c *sqlmock) exec(query string, args []namedValue) (*ExpectedExec, error) {
 	var expected *ExpectedExec
 	var fulfilled int
 	var ok bool
+	var argMismatch error
 	for _, next := range c.expected {
 		next.Lock()
 		if next.fulfilled() {
@@ -157,6 +167,10 @@ func (c *sqlmock) exec(query string, args []namedValue) (*ExpectedExec, error) {
 			if err := exec.attemptArgMatch(args); err == nil {
 				expected = exec
 				break
+			} else {
+				// remember the reason the sql matched but the args did not,
+				// so it can be reported if no other expectation matches
+				argMismatch = err
 			}
 		}
 		next.Unlock()
@@ -166,7 +180,11 @@ func (c *sqlmock) exec(query string, args []namedValue) (*ExpectedExec, error) {
 		if fulfilled == len(c.expected) {
 			msg = "all expectations were already fulfilled, " + msg
 		}
-		return nil, fmt.Errorf(msg, query, args)
+		err := fmt.Errorf(msg, query, args)
+		if argMismatch != nil {
+			err = fmt.Errorf("%s, arguments do not match: %s", err, argMismatch)
+		}
+		return nil, err
 	}
 	defer expected.Unlock()
 

sqlmock_go18.go

@@ -200,6 +200,7 @@ func (c *sqlmock) query(query string, args []driver.NamedValue) (*ExpectedQuery,
 	var expected *ExpectedQuery
 	var fulfilled int
 	var ok bool
+	var argMismatch error
 	for _, next := range c.expected {
 		next.Lock()
 		if next.fulfilled() {
@@ -223,6 +224,10 @@ func (c *sqlmock) query(query string, args []driver.NamedValue) (*ExpectedQuery,
 			if err := qr.attemptArgMatch(args); err == nil {
 				expected = qr
 				break
+			} else {
+				// remember the reason the sql matched but the args did not,
+				// so it can be reported if no other expectation matches
+				argMismatch = err
 			}
 		}
 		next.Unlock()
@@ -233,7 +238,11 @@ func (c *sqlmock) query(query string, args []driver.NamedValue) (*ExpectedQuery,
 		if fulfilled == len(c.expected) {
 			msg = "all expectations were already fulfilled, " + msg
 		}
-		return nil, fmt.Errorf(msg, query, args)
+		err := fmt.Errorf(msg, query, args)
+		if argMismatch != nil {
+			err = fmt.Errorf("%s, arguments do not match: %s", err, argMismatch)
+		}
+		return nil, err
 	}
 
 	defer expected.Unlock()
@@ -283,6 +292,7 @@ func (c *sqlmock) exec(query string, args []driver.NamedValue) (*ExpectedExec, e
 	var expected *ExpectedExec
 	var fulfilled int
 	var ok bool
+	var argMismatch error
 	for _, next := range c.expected {
 		next.Lock()
 		if next.fulfilled() {
@@ -307,6 +317,10 @@ func (c *sqlmock) exec(query string, args []driver.NamedValue) (*ExpectedExec, e
 			if err := exec.attemptArgMatch(args); err == nil {
 				expected = exec
 				break
+			} else {
+				// remember the reason the sql matched but the args did not,
+				// so it can be reported if no other expectation matches
+				argMismatch = err
 			}
 		}
 		next.Unlock()
@@ -316,7 +330,11 @@ func (c *sqlmock) exec(query string, args []driver.NamedValue) (*ExpectedExec, e
 		if fulfilled == len(c.expected) {
 			msg = "all expectations were already fulfilled, " + msg
 		}
-		return nil, fmt.Errorf(msg, query, args)
+		err := fmt.Errorf(msg, query, args)
+		if argMismatch != nil {
+			err = fmt.Errorf("%s, arguments do not match: %s", err, argMismatch)
+		}
+		return nil, err
 	}
 	defer expected.Unlock()
 

sqlmock_go18_test.go

@@ -7,10 +7,49 @@ import (
 	"context"
 	"database/sql"
 	"errors"
+	"strings"
 	"testing"
 	"time"
 )
 
+// When expectations are matched out of order and a query matches by sql but
+// not by arguments, the failure should explain the argument mismatch and
+// include the actual received values, not just report "was not expected".
+func TestUnorderedArgumentMismatchReportsReceivedValues(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Errorf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	mock.MatchExpectationsInOrder(false)
+
+	mock.ExpectExec("UPDATE users").WithArgs("alice").WillReturnResult(NewResult(1, 1))
+	if _, err := db.Exec("UPDATE users SET name = ?", "bob"); err == nil {
+		t.Error("expected an error for the mismatched exec argument, but got none")
+	} else {
+		if !strings.Contains(err.Error(), "arguments do not match") {
+			t.Errorf("expected the error to explain the argument mismatch, but got: %s", err)
+		}
+		if !strings.Contains(err.Error(), "bob") {
+			t.Errorf("expected the error to include the received argument value 'bob', but got: %s", err)
+		}
+	}
+
+	mock.ExpectQuery("SELECT name FROM users").WithArgs(1).WillReturnRows(NewRows([]string{"name"}).AddRow("alice"))
+	if _, err := db.Query("SELECT name FROM users WHERE id = ?", 2); err == nil {
+		t.Error("expected an error for the mismatched query argument, but got none")
+	} else {
+		if !strings.Contains(err.Error(), "arguments do not match") {
+			t.Errorf("expected the error to explain the argument mismatch, but got: %s", err)
+		}
+		if !strings.Contains(err.Error(), "actual [int64 - 2]") {
+			t.Errorf("expected the error to include the received argument value 2, but got: %s", err)
+		}
+	}
+}
+
 func TestContextExecCancel(t *testing.T) {
 	t.Parallel()
 	db, mock, err := New()