What is an operating system?

An operating system (OS) is the Application Which, after being initially loaded into the computer by a boot program, oversees all the other application programs in a computer. The application programs make use of the working system by making Furthermore, users can interact directly with the operating system Via a user interface like a command line or a graphical user interface (GUI).

9 Popular Mobile Operating Systems

Android OS (Google Inc.) ...
2. Bada (Samsung Electronics) ...
BlackBerry OS (Research In Motion) ...
iPhone OS / iOS (Apple) ...
MeeGo OS (Nokia and Intel) ...
Palm OS (Garnet OS) ...
Symbian OS (Nokia) ...
webOS (Palm/HP) ...

Types of operating systems.

Operating systems normally include pre-loaded on almost any Computer you purchase. Many men and women use the operating system which comes with their computer, however it is possible to update or perhaps alter operating systems. The three most frequent operating systems for personal computers are Microsoft Windows, macOS, and Linux. A GUI enables you to use your mouse to click on icons, switches , and menus, and that which is clearly displayed on the display by means of a combo of images and text. Each operating system's GUI includes a different feel and look, so if you Switch to another operating system it might appear unfamiliar at first. However, modern operating systems have been made to be effortless to utilize , and the majority of the fundamental principles are exactly the same.

Microsoft established the Windows operating platform at the mid-1980s. There have been a number of distinct variants of Windows, but the latest ones are Windows 10 (published in 2015), Windows 8 (2012), Windows 7 (2009), along with Windows Vista (2007). Windows includes pre-loaded on many new PCs, which helps to ensure it is the hottest operating system on the planet.
Microsoft Windows
Microsoft established the Windows operating platform at the mid-1980s. There have been a number of distinct variants of Windows, but the latest ones are Windows 10 (published in 2015), Windows 8 (2012), Windows 7 (2009), along with Windows Vista (2007). Windows includes pre-loaded on many new PCs, which helps to ensure it is the hottest operating system on the planet.
MacOS (formerly called OS X) is a Lineup of operating systems made by Apple. It comes preloaded on all Macintosh computers, or Macs. A number of the specific models include Mojave (published in 2018), High Sierra (2017), and Sierra (2016). Based on StatCounter Global Stats, macOS users accounts for significantly less than 10 percent of international functioning systems--considerably lower than the percent of Windows users (greater than 80 percent ). 1 reason behind this is that Apple computers have a tendency to be costlier. But a lot of individuals do prefer the appearance and feel of macOS over Windows.
macOS
MacOS (formerly called OS X) is a Lineup of operating systems made by Apple. It comes preloaded on all Macintosh computers, or Macs. A number of the specific models include Mojave (published in 2018), High Sierra (2017), and Sierra (2016). Based on StatCounter Global Stats, macOS users accounts for significantly less than 10 percent of international functioning systems--considerably lower than the percent of Windows users (greater than 80 percent ). 1 reason behind this is that Apple computers have a tendency to be costlier. But a lot of individuals do prefer the appearance and feel of macOS over Windows.
Linux (pronounced LINN-ux) is a household of open-source operating systems, so they may be altered and distributed by all around the globe. This differs from proprietary program such as Windows, which may only be altered by the organization that owns it. The benefits of Linux are that it's free, and there are several different distributions or variations you may select from. Based on StatCounter Global Stats, Linux users accounts for under 2 percent of international functioning systems. But most servers run Linux since it's relatively simple to personalize.
Linux
Linux (pronounced LINN-ux) is a household of open-source operating systems, so they may be altered and distributed by all around the globe. This differs from proprietary program such as Windows, which may only be altered by the organization that owns it. The benefits of Linux are that it's free, and there are several different distributions or variations you may select from. Based on StatCounter Global Stats, Linux users accounts for under 2 percent of international functioning systems. But most servers run Linux since it's relatively simple to personalize.
The operating systems we have been speaking about so much were created to operate on desktop and notebook computers. Mobile apparatus like telephones , tablets , and MP3 players Are distinct from desktop and notebook computers, so that they run operating systems that have been designed especially for mobile devices. From the screenshot below, you can view iOS running in an iPad. Operating systems for mobile devices normally are not as fully featured As those created for desktop and notebook computers, and they are not capable to Run each the exact same software. But, you can still perform a Great Deal of things Together, like watch videos, browse the net, manage your calendarand play games.
Operating systems for mobile devices
The operating systems we have been speaking about so much were created to operate on desktop and notebook computers. Mobile apparatus like telephones , tablets , and MP3 players Are distinct from desktop and notebook computers, so that they run operating systems that have been designed especially for mobile devices. From the screenshot below, you can view iOS running in an iPad. Operating systems for mobile devices normally are not as fully featured As those created for desktop and notebook computers, and they are not capable to Run each the exact same software. But, you can still perform a Great Deal of things Together, like watch videos, browse the net, manage your calendarand play games.

Riccardo Padovani: Fail a Gitlab pipeline when code coverage decreases

Automatic and continuous testing is a fundamental part of today’s development cycle. Given a Gitlab pipeline that runs for each commit, we should enforce not only all tests are passing, but also that a sufficient number of them are present.

cover

Photo by Pankaj Patel on Unsplash

Aren’t you convinced yet? Read 4 Benefits of CI/CD! If you don’t have a proper Gitlab pipeline to lint your code, run your test, and manage all that other annoying small tasks, you should definitely create one! I’ve written an introductory guide to Gitlab CI, and many more are available on the documentation website.

While there isn’t (unfortunately!) a magic wand to highlight if the code is covered by enough tests, and, in particular, if these tests are of a sufficient good quality, we can nonetheless find some valuable KPI we can act on. Today, we will check code coverage, what indicates, what does not, and how it can be helpful.

Code coverage

In computer science, test coverage is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs. A program with high test coverage, measured as a percentage, has had more of its source code...


Automatic and continuous testing is a fundamental part of today’s development cycle. Given a Gitlab pipeline that runs for each commit, we should enforce not only all tests are passing, but also that a sufficient number of them are present.

cover

Photo by Pankaj Patel on Unsplash

Aren’t you convinced yet? Read 4 Benefits of CI/CD! If you don’t have a proper Gitlab pipeline to lint your code, run your test, and manage all that other annoying small tasks, you should definitely create one! I’ve written an introductory guide to Gitlab CI, and many more are available on the documentation website.

While there isn’t (unfortunately!) a magic wand to highlight if the code is covered by enough tests, and, in particular, if these tests are of a sufficient good quality, we can nonetheless find some valuable KPI we can act on. Today, we will check code coverage, what indicates, what does not, and how it can be helpful.

Code coverage

In computer science, test coverage is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs. A program with high test coverage, measured as a percentage, has had more of its source code executed during testing, which suggests it has a lower chance of containing undetected software bugs compared to a program with low test coverage.

Wikipedia

Basically, code coverage indicates how much of your code has been executed while your tests were running. Personally, I don’t find a high code coverage a significant measure: if tests are fallacious, or they run only on the happy path, the code coverage percentage will be high, but the tests will not actually guarantee a high quality of the code.

On the other hand, a low code coverage is definitely worrisome, because it means some parts of the code aren’t tested at all. Thus, code coverage has to be taken, as every other KPI based only exclusively on lines of code, with a grain of salt.

High code coverage doesn't guarantee a high quality test suite, but a low code coverage definitely highlights a problem in the testing process.

Code coverage and Gitlab

Gitlab allows collecting code coverage from test suites directly from pipelines. Major information on the setup can be found in the pipelines guide and in the Gitlab CI reference guide. Since there are lots of different test suites out there, I cannot include how to configure them here. However, if you need any help, feel free to reach out to me at the contacts reported below.

With Gitlab 13.5 there is also a Test Coverage Visualization tool, check it out! Gitlab will also report code coverage statistic for pipelines over time in nice graphs under Project Analytics > Repository. Data can also be exported as csv! We will use such data to check if, in the commit, the code coverage decreased comparing to the main branch.

This means that every new code written has to be tested at least as much as the rest of the code is tested. Of course, this strategy can be easily changed. The check is only one line of bash, and can be easily be replaced with a fixed number, or any other logic.

The Gitlab Pipeline Job

The job that checks the coverage runs in a stage after the testing stage. It uses alpine as base, and curl and jq to query the APIs and read the code coverage.

On self hosted instances, or on Gitlab.com Bronze or above, you should use a project access token to give access to the APIs. On Gitlab.com Free, use a personal access token. If the project is public, the API are accessible without any token. It needs three variables: the name of the job which generates the code coverage percentage (JOB_NAME), the target branch to compare the coverage with (TARGET_BRANCH), and a private token to read the APIs (PRIVATE_TOKEN). The job will not run when the pipeline is running on the target branch, since it would be comparing the code coverage with itself, wasting minutes of runners for nothing.

The last line is the one providing the logic to compare the coverages.

checkCoverage:
    image: alpine:latest
    stage: postTest
    variables:
        JOB_NAME: testCoverage
        TARGET_BRANCH: main
    before_script:
        - apk add --update --no-cache curl jq
    rules:
      - if: '$CI_COMMIT_BRANCH != $TARGET_BRANCH' 
    script:
        - TARGET_PIPELINE_ID=`curl -s "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/pipelines?ref=${TARGET_BRANCH}&status=success&private_token=${PRIVATE_TOKEN}" | jq ".[0].id"`
        - TARGET_COVERAGE=`curl -s "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/pipelines/${TARGET_PIPELINE_ID}/jobs?private_token=${PRIVATE_TOKEN}" | jq --arg JOB_NAME "$JOB_NAME" '.[] | select(.name==$JOB_NAME) | .coverage'`
        - CURRENT_COVERAGE=`curl -s "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/pipelines/${CI_PIPELINE_ID}/jobs?private_token=${PRIVATE_TOKEN}" | jq --arg JOB_NAME "$JOB_NAME" '.[] | select(.name==$JOB_NAME) | .coverage'`
        - if  [ "$CURRENT_COVERAGE" -lt "$TARGET_COVERAGE" ]; then echo "Coverage decreased from ${TARGET_COVERAGE} to ${CURRENT_COVERAGE}" && exit 1; fi;

This simple job works both on Gitlab.com and on private Gitlab instances, for it doesn’t hard-code any URL.

Gitlab will now block merging merge requests without enough tests! Again, code coverage is not the magic bullet, and you shouldn’t strive to have 100% of code coverage: better fewer tests, but with high quality, than more just for increasing the code coverage. In the end, a human is always the best reviewer. However, a small memo to write just one more test is, in my opinion, quite useful ;-)

Questions, comments, feedback, critics, suggestions on how to improve my English? Reach me on Twitter (@rpadovani93) or drop me an email at This email address is being protected from spambots. You need JavaScript enabled to view it..

Ciao,
R.


Read full article on Planet Ubuntu


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