DEV Community: Anne Quinkenstein

gdb debugger

Anne Quinkenstein — Tue, 31 Oct 2023 14:17:26 +0000

runs on many Unix-like systems and works for many programming languages, including Ada, Assembly, C, C++, D, Fortran, Haskell, Go, Objective-C, OpenCL C, Modula-2, Pascal, Rust,...

strings programm

shows all strings of a programm

./check $(python3 -c 'print("a" * 200)')

gdb debugger

gdb programm (start programm in same folder)
(gdb) disas function
(gdb) b* 0x401402 (set breakpoint)
(gdb) r xxxxxxxx (start Programm with parameter (eg pw))
(gdb) i r (info register) show registger
eg PW: for every letter show:
(gdb) set $al = $dl
(gdb) c

Selenium Page Factory

Anne Quinkenstein — Wed, 12 Jul 2023 08:15:05 +0000

how it works

FindBys - AND Condition

Eg: @FindBys({@FindBy(id = "foo"), @FindBy(className = "bar")})

HTML source code of a WebElement:

In POM:

@FindBys({
@FindBy(id = "searchId_1"),
@FindBy(name = "search_field")
})

WebElementSearchButton;

In the above example, the WebElement ‘SearchButton’ is located only if it matches both the criteria whose id value is “searchId_1” and the name value is “search_field”. Please note that the first criteria belong to a parent tag

and the second criteria for a child tag.

FindAll - OR Condition

@CacheLookUp

if a Webelement is approched several time, you can store it in cache

extended

Alternatives: Actions-Class and Javascript Executer in Selenium

Anne Quinkenstein — Thu, 15 Jun 2023 11:22:48 +0000

Action Class

perform operations from keyboard events and mouse events (even dragging-and-dropping, holding a key and then performing mouse operations, ..)
we can building a complex chain of events exactly like a user doing these manually
The Actions class implements the builder pattern to create a composite action containing a group of other actions.

We need to create an instance of the Actions class by passing the instance of driver class to the constructor in the following way:

Actions a = new Actions(driver);

then we can use the methods of the action Class like MouseOver, ContextClick/RightClick, DoubleClick ...

a.moveToElement(element).conextClick().build().performe();

before performing the action, you have to build the entire element. that enables to composit actions
to execute it you have to invoke performe() !

a.moveToElement(textbox).click().keyDown(Keys.SHIFT).sendKeys("hello").build().performe();

Spring Boot

Anne Quinkenstein — Tue, 18 Apr 2023 16:13:25 +0000

Spring Boot
...
Automatic Controller Mappings for MVC based Applications
few annotations
Auto Config

application Context (inversion of Control container (bean factory) ) -> opinionated configarations

start Project with spring initializer
start.spring.io
-maven oder gradle
java (kotlin, groovy)
package as jar
java 17? welche version?
add dependencies ...
spring web ...
(ID-Plugin possible)
copy files in personal directory (-rekursivly)

main Method -> @SpringBootApplication / use that as base for component scanning & auto-config
ressources -> static/ template ( because of webpackage)
application.properties -> control context

libary-> configured, embedded tomcat

Inversion of Control
Container -> Objects injected at runtime/ starttime (added to BeanFactory)
IoC & Dependency Injection -> objects dont create dependend objects, but container manages them and injects them as needed

IoC Container -> triggered from main class
IoC Container build Objects wich are referenced in Main, pointers in classes,
pointers in classes & IoC Container injects them + manage LifeCycle

Spring IoC -Bean Factory is IoC Container
Hooks //

Application Context to interact <- Spring Boot application, that conext is started for us, and autoconfig
Application Context is wrapper around bean factory

Spring Beans
Spring-> handles Object initilazation, instatiation
Beanfacotry -> beans instatioated in right order

annotations
metadata for code - often use for compiler or runtime instruction (@test)

spring benutzt sie als hebelpunkte für code. add functionality, with proxies

beans in beanfactory are proxied, annotations drive proxies

annotations drive behavior and component scanning as part of the application context
-> scope for calling methods -> calling order matters

Spring Data
provides a commen set of interfaces based on JPA
interface for JDBC, easier
repository pattern nativly
key benefits of key data
swap datasources is easy
SPring data repository provides the methods needed to access the data
interface leverage proxies that builds the actual CRUD methods
Entity Objects
Data Sourced autoconfigured by Spring Boot

embedded Database

tomcat on 8080

SQL Cheet Sheat

Anne Quinkenstein — Mon, 12 Dec 2022 17:32:04 +0000

Data Definition Language

CREATE SCHEMA hollywood;
CREATE TABLE hollywood.films (title text, release date, awards
text[]);

CREATE TABLE personen
(ID INTEGER PRIMARY KEY,
Name CHAR(30) NOT NULL,
Abteilung VARCHAR(5),
Telefonnummer TEXT, 
Postleitzahl NUMERIC,
Name_des_Wohnorts CHAR(30),
Jahr_der_Einstellung DATE REFERENCES Abteilung); //secondary Key

Data Manipulation Language

insert into Vorlesungen (VorlNr, Titel, SWS, gelesenVon)
values (5099, `Methaphysik‘, 4, 2137);

insert into hören
select MatrNr, VorlNr
from Studenten, Vorlesungen
where Titel= `Logik‘ ;

update Studenten set Semester= Semester + 1;
delete

Data Query Language

select

select distinct ..
SELECT a, a*100/c AS percentage
SELECT a "given as an A"COUNT(*)with wildcard counts every line orCOUNT(name)counts every filled line,COUNT(distinct name)`

sort

select name from personen order by Rang desc,Name asc

Join

FROM (student s JOIN personen h ON (s.Matr_nr=h.Matr_nr and s.Name='Lovelace')
students JOIN lectures v USING Vorl_nr
students NATURAL JOIN lectures
students LEFT JOIN lectures also students without a lecture are in table

UNION, INTERSECT, EXCEPT

find all: select name from assistent) union (select name from professors)

LIKE

wildcard "%" ; ""
"%" any amound
"" exactly one char
where title like '%thik%';

notin, all, ect

ect: 'avg(age), max(age), min(age), count(*), sum(meter)`

where PersNr not in (select gelesenVon from Vorlesungen );
where Semester >= all ( select Semester from Studenten);
same as: where Semester >= ( select max(Semester) from Studenten);
`

group by

select gelesenVon, Name, avg(SWS) from Vorlesungen, Professoren where gelesenVon = PersNr group by gelesenVon, Name having avg(SWS) >= 3;

Query in FROM

FROM(SELECT * FROM Studenten s JOIN hoeren h USING (Matr_nr)
WHERE s.Name='Lovelace') lovelace_hoert`
has to have a name

declutter querys

With alias_name1 as
(select ...from... where...),
alias_name2 as
(select ...from... where...)'

select * from Studenten where Semester between 1 and 4;
select * from Studenten where Semester in (1,2,3,4);

select MatrNr, (case when Note<1.5 then ‘sehr gut‘
when Note<2.5 then ‘gut‘
when Note<3.5 then ‘befriedigend‘
when Note <= 4 then ‘ausreichend‘
else ‘Nicht bestanden‘ end)
from pruefen;

select s.MatrNr, s.Name, avg(Note) as persDurchschnitt,
(select avg(note) as Gesamtsschnitt from pruefen p)
from Studenten s, pruefen p
where s.MatrNr=p.MatrNr
group by s.MatrNr, Name
having persDurchschnitt < select avg(note) from pruefen p

Git for Beginners

Anne Quinkenstein — Wed, 07 Dec 2022 10:32:50 +0000

Git on your Local machine:

Check if you have Git on your local machine: git --version
If not, install it on linux,mac or win.

Set your username: git config --global user.name "FIRST_NAME LAST_NAME"
Set your email address: git config --global user.email "MY_NAME@example.com"

Which command allows you to transform a classic folder into a local git project? git init
Which command allows you to move a file to the staging directory? git add
Which command allows you to create a commit? git commit

let's talk SSH

github-doc
The instructions you have followed in this tutorial have created 2 files in your /home//.ssh/ folder :

the first one (id_ed25519) : this is your private key, you must NEVER publish it or share it with anyone, it must exist on your computer only;
the second one (id_ed25519.pub) : this is your public key, that you will share on GitHub following the instructions in the next step of this quest.

add your public key in your GitHub settings

tutorial

You can save multiple SSH keys on you GitHub account. For example, if you want to work with Git and GitHub from different computers, you will have to repeat those steps one by one on each of your computers, so that they each have their own SSH key linked to your GitHub account.

set up a remote repository by using git remote add origin <REMOTE_URL> or git clone <REMOTE_URL>

the one you need starts with git@github.com: .When using this address (for example by running git clone git@github.com:/ in your local Git repository), your repository will be configured to use SSH authentication with the keys you created and configured in GitHub earlier. Thanks to SSH athentication, you don't have to enter your GitHub username and password, the authentication process is automatic.

Finding the git@github.com: url of a remote repository is quite simple : just go to the repository in question on GitHub, and click on the green "Code" button. Select "SSH", copy the address it displays, and that's it!

send your sources to a remote repository

git remote add origin <REMOTE_URL>
confirm by git remote -v

Push: To upload information from the local repo to the remote repo.

git push origin main

Retrieve changes

git pull origin main
which is actually this two:
git fetch origin
git merge origin/main

Copy remote repository to your local machine

git clone <REMOTE_URL>

follow the flow - branching

create a new branch git checkout -b <branchName>
switch to a exciting branch git checkout <branchName>
to check which branch you are on git branch -a
which are exciting git branch
delete a branch locally (jump off +) git branch --delete <branchName>

merging code between branches

when merging, we need to be on the branch that we want to merge to. Basically, we will be telling git, “See that new thing? It’s ok to bring it over here now.”
git merge –no-ff <branchName> — the additional –no-ff tells git we want to retain all of the commit messages prior to the merge.
To delete a merged branch: git branch -d <branchName>

merge conflict

If we do a git status it should still show our conflict. Since we want to keep the one from my new version, simply delete the lines that Git plopped in there and the old version. Then just add and commit the file as normal, and your merge is resolved!

stash

add your changes to the index using git add .
stash your changes away: git stash
bring your changes back: git stash apply
if you got multiple layers of stashes: git stash list
apply the second stash git stash apply stash@{1}
deletes that stash for good: git stash drop <id>
delete all of the stored stashes: git stash clear

reverting files

git tagging

$ git tag to list existing tags
lightweight tag git tag TAG_NAME
annotated tag git tag -a v1.0 -m "Version 1.0"
git push origin --tags

Selenium Testautomation on Windows Desctop App with Winium (Java)

Anne Quinkenstein — Mon, 30 May 2022 14:27:37 +0000

https://github.com/2gis/Winium

Winium = Windows + Selenium
open source
works with all WebDriver compatible languages (Java, Python, ..)
only for client-based applications on Windows (not IOS or Linux)

Prerequisites

Microsoft .NET Framework 4.5.1
Winium.Desktop.Driver.exe

Some other dependencies that are downloaded using the Maven file, as mentioned in the POM file below:

add dependencies to pom-file

download winuiumDriver from github
appPath:put it somewhere in the windows explorer

Code

By initiating the Winium driver using the Winiumdriver class, we are passing the Winium server URL and the path of our desktop application on which automation is intended to be carried out.

The server URL is obtained by clicking on the Winium.desktop.driver.exe that was downloaded.

... throws MalformedURLException

DesktopOptions desktopOptions = new DesktopOptions();
desktopOptions.setApplicationPath(configFileReader.getAppPath());   desktopOptions.setKeyboardSimulator(KeyboardSimulatorType.BasedOnWindowsFormsSendKeysClass);
//winiumDriver with URL:: localhost:9999, every call we make goes through this driver .... 
winiumDriver = new WiniumDriver(new URL("http://localhost:9999"), desktopOptions);

By initiating the Winium driver using the Winiumdriver class, we are passing the Winium server URL and the path of our desktop application on which automation is intended to be carried out.

3 conditions

path to winium driver and setup
start winium driver (dobbleclick)
run tests

how to inspect the Desctop Desctop Elements (or Java Forms based)?

inspect.exe to identify the element locators in Windows applications.
https://kb.froglogic.com/squish/howto/getting-information-toolkits-gui-controls-windows/
We can identify the element using the name, ID and xpath.

all in all:
The main difference between Selenium and Winium is that selenium automatically creates its session on localhost with a unique port, but in Winium, we have to create sessions manually through its exe file. Besides this, running an automation service through Winium needs the user to run a local server that supports the script, i.e., Winium server, whereas automating windows applications using Selenium does not require such efforts. The driver it will open by default with port 9999 which acts as a server.

Internally this server will communicate through JSON Wireless Protocol

Network via Terminal

Anne Quinkenstein — Wed, 18 May 2022 18:48:51 +0000

lshw -class network
Logical name of the network adapter: eth0
Serial number of the network adapter (= MAC Adress) b8:27:eb:5c:c4:37
ip addr show eth0

Status: up/down (on and off)
MAC Adress: consists of 8 hexadecimal numbers
IPv4: 10.10.10.86 consists of 4 numbers between 0 and 255
IP- Broadcastadresse Gateway Rechner

ip-neigh
eigenen Rechner + Broadcast Rechner + ggf die, die mich angepingt haben

ping IPv4-Adresse - geht, dann auch Rechner mit ip-neigh sichtbar

Aus Sicherheitsgründen antworten Hosts standardmäßig nicht auf pings an die Broadcastadresse. Dies können Sie jedoch explizit mit dem folgenden Befehl erlauben: sudo sysctl net.ipv4.icmp_echo_ignore_broadcasts=0

WLAN
vorhandenen WLAN-Access Points mit dem Befehl sudo iw wlan0 scan
sudo iw wlan0 scan | egrep "^BSS|SSID"
iw ist ein Kommandozeilenwerkzeug zur Konfiguration von WLAN-Geräten
BSS (noch ein weiterer Name für die MAC-Adresse bei WLAN-APs) und den Namen des WLANs (SSID)

iw wlan0 link iw ist speziell Wlan (Info WLan?)

sudo shotdown all - rasberry runterfahren

Kontrollieren Sie die Signalstärke mit dem Befehl:sudo iw wlan0 scan | egrep "SSID|signal"

Die Übertragungsfrequenz gibt als Nyquist-Frequenz das obere theoretische Limit für die maximale Übertragungsrate vor
tatsächliche Übertragungsfrequenz (tx bitrate)

rx recieved
tx transmitted

ip -s link show ADAPTER

RX bedeutet Receive, also Empfangen von Daten, TX bedeutet dabei Transmit, also das Senden von Daten.
Die ersten beiden Spalten (bytes packets) geben die Gesamtzahl an übermittelten Daten an, seit der Netzwerkadapter gestartet wurde.
errors gibt die Anzahl an fehlerhaften Paketen (z.B. aufgrund zu schlechter Signalqualität) an.
dropped gibt die Anzahl der Pakete, die vom Netzwerkadapter weggeworfen wurden, an. Dies kann passieren, wenn der Netzwerkadapter überlastet ist oder das übemittelte Paket nicht die richtige Größe hat.
overrun gibt die Anzahl der Pakete, die nicht bearbeitet wurden, weil der interne Speicher des Netzwerkadapters übergelaufen ist.
Carrier gibt die Anzahl der Pakete, die aufgrund der fehlenden Verbindung des Übertragungsmediums nicht übertragen werde konnten.
mcast sind die per Multicast gesendeten Pakete.

Building a Selenium Framework

Anne Quinkenstein — Tue, 08 Feb 2022 09:22:39 +0000

Create a Maven Project

1. Create new Maven Project

-> Maven - new Project - maven-quickstart - GroupID + ArtifactID

2. Add all Dependencies in pom.xml

Add from Maven Repro: Selenium & TestNG

3. Create Base and utility functions

Create base Class in main/java & add Browser Invocation

create a resources Package in main/java
create a file "data.properties" to store data in a central place store things like browser = chrome
envoce it in the base.file

Properties prop = Properties(); 
FileInputStream fis = new FileInputStream("//home//helloworld//Documents//Code//Ecplise//SampleProject//E2EProject//src//main//java//SampleProject//data.properties"); 
prop.load(fis);
String browsername = prop.getProperty("browser");

Find absolute path of data.properties in rightclick Properties
put it in the FileInputStream

if (browserName == "chrome") 
{
            System.setProperty("webdriver.chrome.driver", "C://home//helloworld//chromedriver"); 
driver = new ChromeDriver(); 
} else if .... 
....
// instead of former implicitly Wait: 
new WebDriverWait(driver, Duration.ofSeconds(10));
return driver;

4. Organizing Page objects

Adding Tests
Datadriving/ Prameterizing Tests
Converting into TestNG Framework
TestNG Listeners
Screenshot on Test Failures
Creating Excellent HTML reports for Test Results
Jenkins Continuous Integration

JUnit 5

Anne Quinkenstein — Thu, 27 Jan 2022 11:01:29 +0000

1. Do a Maven Project

2. Change pom.xml

Search for lastest JUnit-Jupiter (Aggregator) in Maven(Aggregator downloads every dependencies )

 <dependencies>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter</artifactId>
        <version>5.8.2</version>
        <scope>test</scope>
    </dependency>
  </dependencies>

Change Configuration of the Maven Plugin to JDK8 and higher (required Java Version)

 <plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
            <source>8</source>
            <target>8</target>
        </configuration>
    </plugin>
</plugins>

3. Write Tests

any class that contains at least one test method is considered a test class.
access Modifier should NOT be private
return Type is always void

package junit5tests;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

public class firstTest {

    @Test
    void firstMethod() {
        System.out.println("This is the first test method");
    }

    @Test
    @DisplayName("US1234 - TC12 - this method is the second one")
    void secondMethod() {
        System.out.println("This is the second test method");
    }
}

4. Lifecycle Methods

There are @BeforeAll Annotations for Setting up something before the Tests and @BeforeEach to set up before each Testcase. Cleaning up is done with @AfterAll, @AfterEach Methods.

   @BeforeAll
    void beforeAll() {
        System.out.println("--This is the before All method");
    }


    @BeforeEach
    void beforeEach() {
        System.out.println("----This is the before Each method");
    }

    @AfterAll
    void afterAll() {
        System.out.println("--This is the after All method");
    }


    @AfterEach
    void afterEach() {
        System.out.println("----This is the after Each method");
    }

6. Parameterize Test

6.1. constant values or literals

instead of @test annotation -> @ParameterizedTest
@ValueSource annotation to pass (just) ONE Value -> use an Array e.g. int[] or String[]
it will run throught the array and pass each parameter to the method -> so the methods takes one param of the type of the Array. e.g. void intValues (int theParam)
(we have to pass the values, cant pass methods that generates the value)

to beautify it, add round brakets to PramiterizesTests + add Tests with w.g. {index} No of Runs and {arguments} the value of the Param used.

Strings:
pass an Empty String: @EmptySource
pass a null value: @NullSource
pass both: @NullAndEmptySource

public class ParamiterizedTests {

    @ParameterizedTest(name = "Run: {index} - value: {arguments}")
    @ValueSource(ints = {1,5,6})
    void intValues(int theParam) {
        System.out.println("theParam = " + theParam);
    }

    @ParameterizedTest(name = "Which Run? {index} - What did we use? {arguments}")
//  @EmptySource
//  @NullSource
    @NullAndEmptySource
    @ValueSource(strings = {"firstString", "secondString"})
    void stringValues(String theParam) {
        System.out.println("theParam = " + theParam);
    }

}

Some Online Coding Games to Build Your Programming Skills

Anne Quinkenstein — Fri, 21 Jan 2022 17:02:56 +0000

Programming

for Kids

Security

CTF and others

Komlexität von Algorithmen

Anne Quinkenstein — Thu, 02 Dec 2021 19:51:11 +0000

Was ist ein Algorithmus?

EVA Prinzip

Grundprobleme

Berechenbarkeit
Korrektheit
Terminiertheit
Komplexität (Wie lange?)

Eigenschaften

Determiniertheit (Kommt dasselbe bei dem selben Input raus?)
Determinismus (Gibt es immer eindeutig eine nächste Anweisung?)
Finitheit (gibt es ein Ende?)
Effektivität (Ist der Effekt jeder Anweisung klar?)

Komplextität eines Algorithmus

O-NOTATION

•Komplexitätsklassen werden in O-Notation angegeben -> f ∈ O(g)
•Bei dieser Angabe gilt: "g dominiert f"
•f ∈ O(g) ⟷ es gibt n0, c ∈ ℕ, so dass f(n) ≤ c × g(n) für alle n ≥ n0

Häufig benutzte Komplexitätsklassen

•O(log(n))
•O(n log(n))
•O(n)
•O(n2)
•O(2n)

konstant: O(1);
logarithmisch: O(log n), O(log² n)
linar: O(n)
linar-logarithmisch: O(log n * n)
quadratisch: o(n²)
kubisch: O(n³)
exponentiell: O(2hochn)
falkutlät: O(n!)

Analysen von Programmen
wenn sich mit jeden Schritt das Problem halbiert: logarithmische Komplexität
schleife in schleifen: quadratische