A method of testing workpieces and an automated oscillating solution spray manifold assembly for a corrosion testing chamber is configured to introduce a fluid into a cavity of a test cabinet that receives workpieces. The manifold assembly includes a motor having an output shaft for driving a linkage assembly. An elongated spray bar is connected to the linkage assembly and the spray bar has a plurality of openings spaced therealong. The linkage assembly is configured to rotate the spray bar in a desired oscillatory movement such that fluid can be dispensed through the openings and into the test cabinet. A fan-like pattern sprays from one opening and substantially overlaps with spray from at least one adjacent opening. The method of testing may include one or more of the steps of controlling a speed of the motor, a temperature level of the cavity, a humidity level of the cavity, and a salinity content of the fluid within the cavity of the test cabinet.