A testing apparatus for a fuel injector (60, 160) for delivering fuel into an internal combustion engine, in use, wherein the fuel injector under test comprises an inlet for receiving fluid to be injected during a test and a nozzle end for delivering the fluid through an injector outlet, in use, the testing apparatus comprising: an upper mount for receiving the inlet of the fuel injector under test; a lower mount located beneath the upper mount for receiving the nozzle end of the fuel injector under test; at least one of a removable inlet adaptor for use with a fuel injector under test of a first type, wherein the inlet end of the fuel injector under test of the first type fits into the inlet adaptor to allow a flow of fluid to be delivered through the inlet adaptor to the fuel injector under test of the first type, the inlet adaptor being removable from the upper mount when the fuel injector under test is of a second type, or being interchangeable with a different inlet adaptor when the fuel injector under test is of a second type; and a removable outlet adaptor for use with a fuel injector under test of a first type, and being removable from the lower mount when the fuel injector under test is of a second type or being interchangeable with a different outlet adaptor when the fuel injector under test is of a second type, the testing apparatus further comprising a fluid flow measurement device, located downstream of the fuel injector in an outlet line from the fuel injector under test, wherein the fluid flow measurement device is provided with a damper device (28; 200) to limit fluctuations in fluid pressure within the outlet line and, wherein the damper device (28; 200) includes a damper inlet and a damper outlet and at least one chamber (210, 218; 230, 232) located in a flow path between the damper inlet and the damper outlet, and a restriction (212, 220; 242, 244) located at an exit port from at least one of the chambers (210, 218; 230, 232), wherein the restriction (212, 220; 242, 244) is positioned so that fluid exits through the restriction rather than filling the chamber completely, thereby defining a cavity within the chamber which is filled with trapped air at atmospheric pressure which acts as a damping medium for fluid flowing through the damper device during injector testing. an upper mount for receiving the inlet of the fuel injector under test; a lower mount located beneath the upper mount for receiving the nozzle end of the fuel injector under test; at least one of a removable inlet adaptor for use with a fuel injector under test of a first type, wherein the inlet end of the fuel injector under test of the first type fits into the inlet adaptor to allow a flow of fluid to be delivered through the inlet adaptor to the fuel injector under test of the first type, the inlet adaptor being removable from the upper mount when the fuel injector under test is of a second type, or being interchangeable with a different inlet adaptor when the fuel injector under test is of a second type; and a removable outlet adaptor for use with a fuel injector under test of a first type, and being removable from the lower mount when the fuel injector under test is of a second type or being interchangeable with a different outlet adaptor when the fuel injector under test is of a second type, the testing apparatus further comprising a fluid flow measurement device, located downstream of the fuel injector in an outlet line from the fuel injector under test, wherein the fluid flow measurement device is provided with a damper device (28; 200) to limit fluctuations in fluid pressure within the outlet line and, wherein the damper device (28; 200) includes a damper inlet and a damper outlet and at least one chamber (210, 218; 230, 232) located in a flow path between the damper inlet and the damper outlet, and a restriction (212, 220; 242, 244) located at an exit port from at least one of the chambers (210, 218; 230, 232), wherein the restriction (212, 220; 242, 244) is positioned so that fluid exits through the restriction rather than filling the chamber completely, thereby defining a cavity within the chamber which is filled with trapped air at atmospheric pressure which acts as a damping medium for fluid flowing through the damper device during injector testing.