ShortWave

 

Love this application, available on Linux. I did check, but it does seem to be exclusive to Linux.

I came across it fortuitously while looking for radio-related applications in my software manager. There are literally 1000s of stations available for your listening pleasure, entirely justifying the excellent appellation.  

As a child, I whiled away many a happy hour oh so carefully turning a dial on an analogue short wave radio to bring in distant stations. And who can forget the mystery of the numbers stations, and the feeling that if you listened long enough the mystery would be revealed.

On a practical note, the BBC has decided you can't listen to its stations online unless you log in, and you don't with this (need to log in, that is). Just search for the station and click on the one you want to listen to. 

You can also choose to create library of stations you want. Here, I'm going to add BBC Radio 3 to my library. 

And, below, my limited library: 

 

JMeter Refresher

Again, as with my previous post, it's best to think of this as my course notes. These are meant for me to revisit and understand. I believe it's important to make your learning as accessible to you as possible. Often the way something's explained can be a barrier to your understanding, making it (usually unintentionally) sound more complicated than it actually is. Unfortunately, this puts a lot of people off learning, which is a shame. 

Firstly, I want to record the commands for reports. Note: I'm on a Linux machine. 

If you have an existing results file: sh jmeter -g somefile3.csv -o report-output/mytestreports1 -- this is really easy way to make pretty HTML reports out of existing results files. 

This is how to run the whole kit and kaboodle from the command line. You will need to have created the test in JMeter. 

sh jmeter -n -t "location of jmx test file" -l "location of result file" -e -o "location of reports folder"

And below an actual example: 

sh jmeter -n -t "TrainingHTTPTest.jmx" -l somefile9.csv -e -o "testreporting" 

It's worth noting that, apart from the test file (the one with the jmx extension), the other files, if they don't exist will be created. So you could do it again, thus:

sh jmeter -n -t "TrainingHTTPTest.jmx" -l resultfile12.csv -e -o "testreporting1"

For this simple test, the result file looks like this:

And a report, like the one above, will be created in a folder called testreporting1.

Apparently, when you're running a real-world performance test, you shouldn't be doing it from the GUI with lots of listeners, since this produces overhead. I knew this, and I know it can be important to ring every millisecond out of a performance test. 

So now to JMeter, which is where you create your case.  

You will need the following: 

• thread group (think users: this simulates the amount of users)

• a sampler to your thread group (sampler: think the request you want to make, the thing you want to do)

• a listener (you need at least one of these to have any feedback. There are quite a few to choose from depending on the format you're after). Below is a listerner showing two runs, one that failed and one that passed:

You can use the following:

• assertions (for example, the right code is returned, or a certain word appears on a page)
• config element (these run before the sampler and set up initial conditions -- usually for the whole test plan (I think). 
• pre-processors (things you want to have considered before the sampler runs)
• post-processors (essentially doing something with the response)

Order of execution of JMeter elements:

• Configuration elements
• Pre-processors
• Timers
• Samplers
• Post-processors
• Assertions
• Listeners

I went through Raghav Pal's JMeter Masterclass as a refresher course, which can be found here: 

https://www.youtube.com/watch?v=SoW2pBak1_Q

It was a good refresher course, and reminded me that I'd probably made a six course dinner of some things first time round, by which I mean I over-thought and over-complicated them. I must have been in a bad mood last time I installed the Plugins Manager because I remember it as a bit of a faff. It's actually straightforwardly downloading a jar file and putting in a specific folder (learning's all about being in the right mood):

Restart your JMeter and you'll see it under the Options menu, thus:

Performance testing is an important non-functional aspect of testing. Increasingly, customers for software are interested in questions like: How will this behave under load? How many users can I have use a single instance at one time? And more granular questions, such as how long does each process take, or how long does your web application take to move from one process to the other. Can it do parallel processing, etc? JMeter is a free open source tool to answer these question. It's also something of an industry standard. 

I ignored the part of the course that referred to BlazeMeter, preferring to use the Test Script Recorder in JMeter instead. 

The next part of the course covers using JMeter for API testing, which I'll cover in another post. 

Curling up

I spent Sunday morning (and some of the evening) with Curl and a tutorial. These are simply my course notes.

Curl is a bash/command line application that lets you do multiple different things. I use Linux, so Curl comes as standard. I believe it also comes as standard on a Mac. It used to be a bit of a faff on Windows, but now it comes as standard on W10 and 11. 

To download a web page, do this:

curl -L https://www.bbc.co.uk/sport/rugby-union > beebrugbyunionpage.html

What the above will do is download the source code of the rugby union web page into a file called beebrugbyunionpage.html, which you can then open in your browser. The response in the command line will look like this: 

If you then find your file in your file manager and open it, you will see the web page, thus (note the "URL"):

For the sake of understanding, let's get rid of this bit: "> beebrugbyunionpage.html". So, we're now running: 

curl -L https://www.bbc.co.uk/sport/rugby-union

The above command will return all the source code to your command prompt, thus:

And, as you can see from the position of the scroll bar, it goes on a bit. The point is, though, if you copied all of it and saved it in a file with an .html extension, you would have exactly the same file as the one created by "> beebrugbyunionpage.html". The -L switch tells Curl to follow redirects, which are very common. 

If you wanted to get only the headers from the same page, you would do the following: 

curl --head https://www.bbc.co.uk/sport/rugby-union

Which would return something like this:

Just for the sake of it, I tried this:

curl --head https://www.bbc.co.uk/sport/rugby-union > headers.html

When you open that in a browser, it looks like this:

Note: curl -I and the URL will also bring back only the headers. As far as I can gather, curl -I and curl --head do exactly the same thing. 

I had some chat on Mastodon while I was doing this and someone sent me this: 

curl parrot.live -- which will give you a boogying ASCII parrot.

And this:

curl http://wttr.in/Plymouth -- which will give you the weather in the named town. It looks like this in the command line:

And this:

curl qrenco.de/example.eu  -- will create a QR code for the stated link. I'm a bit suspicious of QR codes and don't have a phone that can read them. 

To get details of the client-server interaction, do the following: 

curl -v https://www.bbc.co.uk/sport/rugby-union -- which will return a lot of detail.

curl --trace file.txt  https://www.bbc.co.uk/sport/rugby-union -- which will produce a file called file.txt with a lot of detail and looks something like this (though it goes on for a bit):

Don't know why the below isn't exactly the same, but it isn't:

curl --trace https://www.bbc.co.uk/sport/rugby-union > file2.txt -- produces the following error: "curl: (2) no URL specified"

To send headers in a request, do the following:

curl -H "Accept:SomeHeader/JSON" https://reqres.in/api/users/2 

Apparently, the following is what's expected, though I'm not sure why: 

And now for a POST request:

curl https://reqres.in/api/users --data "name=morpheus&job=leader" -- this will return the following:

It's somewhat different, however, if you want to use the entire JSON, which looks like this:

I have to get this in a single line, so:  {"name": "morpheus", "job": "leader"}

So your curl should look like the following:

curl -X POST -H "Accept:application/json" https://reqres.in/api/users -d '{"name": "morpheus", "job": "leader"}'

And this is what you're after by way of response:

And similarly a PUT request (with -i added to get the headers): 

curl -i -X PUT https://reqres.in/api/users/2 -d '{"name": "morpheus", "job": "accountant"}'  -- returns the following:

And, finally, before I curl up into a ball, a DELETE request: 

curl -i -X DELETE https://reqres.in/api/users/2 -- and you should get the following response (204 means it's been deleted):

Apparently, there's a lot more you can do with Curl, but that's for another day. But I might end this post by doing the following after I've posted it:

curl https://techstuffandnonsense1.blogspot.com/2024/09/ > curling-up.html

And now if you go to your file manager and locate curling-up.html and open it, you will see the following: 

Time to curl up with a nice cup of tea.

Following instructions; avoiding assumptions (part 2): writing the ISO to a USB drive

The Linux Mint .iso image has been downloaded to your computer and is probably in your Downloads folder on your hard disk: 

linuxmint-22-cinnamon-64bit.iso

We now need to write it to our USB drive. A reminder of our mission statement:

Linux Mint is a popular Ubuntu-based distribution that we're going to download as an .iso file; we're then going to write the .iso to a USB thumb drive and boot into the live environment. This will allow you to explore Linux without making any changes to your computer. If we're happy with the live environment, we're going to take the next step and install it on our computer. 

We've done the first bit. To write the image to our USB drive we will need a tool like Rufus (on Windows) or Balena Etcher (available for Windows, Mac, and Linux). I'm going with Etcher, but other tools are available. Etcher is free for individual use and can be downloaded from here:

https://etcher.balena.io/

Scroll down and you will see the following: 

Choose "Download" next to the one that fits your operating system. With Etcher installed, open it. It will look like the following:

Choose to "Flash from file". This will open your file manager. Navigate to the .iso and select it. File will be selected, and you will move on to the next stage. 

Click on "Select target". A select target box will open with a list of available drives. This is what it looks like on Linux. Here it's sensibly showing only the USB I've plugged in, and NOT the hard disks in my computer. 

However, it could display other disks. The point is you need to be sure of your target BECAUSE everything on the target will be overwritten, and that would make for a very bad day if you get it wrong. So plug in your USB drive, identify it, and choose that as the target when running Etcher.

Once the file and target have been selected, simply click Flash and the process will begin. Be patient and wait for Etcher to tell you the process has completed. 

Close everything down, remove the USB thumb drive, and back away from the computer. Nothing has changed except that you now have an operating system on the USB drive that can be booted, used, and ultimately installed on any number of computers. For free. Legally. 

I wondered if I should end this by booting triumphantly into the live environment, but decided it would be a better fit for the start of "(part 3)". In "(part 3)", we'll be booting to the USB drive, using the system for a while without making changes to our computer, and ultimately then taking the big step of actually installing the system on to our computer. 

Apache JMeter

I once had an acquaintance -- a moved-on colleague -- who worked exclusively with JMeter, or so he claimed. His job title was Performance Tester, and I was led to understand that JMeter was all about performance testing, load testing, stress testing.  I remember being somewhat surprised because at that point I had been naively oblivious to the specialist trends in IT. He had mastered one piece of software and was making a good living at it. I asked him if it was hard, and he said, "No, I just push a button, wait for the run to end, produce the report, and repeat with a different number of users. Sometimes I change the environment it's pointing at."

I asked if it was hard to set up, and he replied that he hadn't set it up. The setup had been done before he arrived. That occasionally something went wrong and he had to work out what it was and fix it, which could be fiddly and tiresome. These bumps in the road apart, he liked his job and had it down pat. 

Other than my above former colleague, I've never met anyone who likes JMeter. There are tutorials explaining how straightforward it is, how easy to master it is, how widely used it is, etc, lifting your heart and soul to the sure and certain knowledge that you, too, can become a performance guru. And then you point it at the software that is your bread and butter and it's glitch after glitch, error after error, frustration after frustration. I don't know anyone who thinks it's intuitive, Oh, and I remember the fun we had setting up the Firefox proxy for JMeter, which promised to make everything plain sailing. Except it didn't.

Perhaps you think this is just me. Sour grapes on the part of someone who couldn't get to grips with it. It truly isn't. I'm someone more than ready to blame my lack of understanding ahead of blaming the tool. No, I've discussed JMeter with many testers who have used it for its intended purpose and they've come away frustrated... and relieved when they get a break from it. 

Lest this all seem like protracted gripe, it's actually a prelude to me spending some days doing Raghav Pal's JMeter Masterclass, which can be found here: 

https://www.youtube.com/watch?v=SoW2pBak1_Q

I'm currently enjoying learning Katalon, but it's good to break it up a bit. Who knows? I may chance upon a tool that really suits me.