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Origins of Unit Testing in hardware?
According to the Wikipedia entry for Unit Testing, it is defined as a technique for testing components of a system in strict isolation from each other, and it is described as having been expressly invented for Software, and having only been applied to Software. In that same Wikipedia entry we read that the first reference to anything even remotely resembling Unit Testing was in a 1956 U.S. Navy Symposium about software, and then again in 1964, in the context of the software developed for NASA's Mercury Project. However, I once came across a different source, which suggested otherwise. According to that source, Unit Testing in software is an adaptation of preexisting testing techniques for analog electronic hardware. This claim sounds plausible, since in electronic hardware, the operation of each component on a PCB is affected by the mere presence of other components on that same PCB, so in order to locate a defect it is of vital importance to test each component in isolation. Additionally, virtually all early computer hardware was analog, and all early programmers were involved with hardware to a greater or lesser degree, (or should I say to a great or greater degree?) so it is reasonable to assume that the first testing methods for software were inspired by existing testing methods for hardware. Nonetheless, I have to wonder whether this is actually true, and unfortunately, I have forgotten where I first encountered the claim. So, does this claim ring any bells to anyone? Can you please help me find the original source of this claim, or otherwise attest, from personal knowledge, that it is in fact true? What I am essentially looking for is historical references to a systematic approach for testing components (units) of a system in strict isolation from each other, in the context of electronic hardware, before software testing was even a thing. Such an approach would not necessarily be named "Unit Testing", but its aim would have to be the same as the aim of Unit Testing, which is Defect Localization: being able to tell with certainty which unit has a defect, which is impossible when the components are interconnected and therefore interfering with each other. Here is a discussion corroborating this claim, which though is completely devoid of any references to sources: Reddit.com - When was unit testing first invented? In the mean time I have gone ahead and repeated this claim in an answer of mine to a question here on Software Engineering, and I do not feel comfortable about the fact that the claim that I have made is not backed by a reference to a source.
According to the Wikipedia entry for Unit Testing, it is defined as a technique for testing components of a system in strict isolation from each other, and it is described as having been expressly invented for Software, and having only been applied to Software. In that same Wikipedia entry we read that the first reference to anything even remotely resembling Unit Testing was in a 1956 U.S. Navy Symposium about software, and then again in 1964, in the context of the software developed for NASA's Mercury Project.
However, I once came across a different source, which suggested otherwise.
According to that source, Unit Testing in software is an adaptation of preexisting testing techniques for analog electronic hardware.
This claim sounds plausible, since in electronic hardware, the operation of each component on a PCB is affected by the mere presence of other components on that same PCB, so in order to locate a defect it is of vital importance to test each component in isolation. Additionally, virtually all early computer hardware was analog, and all early programmers were involved with hardware to a greater or lesser degree, (or should I say to a great or greater degree?) so it is reasonable to assume that the first testing methods for software were inspired by existing testing methods for hardware.
Nonetheless, I have to wonder whether this is actually true, and unfortunately, I have forgotten where I first encountered the claim.
So, does this claim ring any bells to anyone?
Can you please help me find the original source of this claim, or otherwise attest, from personal knowledge, that it is in fact true?
What I am essentially looking for is historical references to a systematic approach for testing components (units) of a system in strict isolation from each other, in the context of electronic hardware, before software testing was even a thing. Such an approach would not necessarily be named "Unit Testing", but its aim would have to be the same as the aim of Unit Testing, which is Defect Localization: being able to tell with certainty which unit has a defect, which is impossible when the components are interconnected and therefore interfering with each other.
Here is a discussion corroborating this claim, which though is completely devoid of any references to sources: Reddit.com - When was unit testing first invented?
In the mean time I have gone ahead and repeated this claim in an answer of mine to a question here on Software Engineering, and I do not feel comfortable about the fact that the claim that I have made is not backed by a reference to a source.
