Test class for Case History Related list
Is it possible to test apex that relies on field history tracking?
Why is Minecraft giving an OpenGL error? I recently got Minecraft but not from the website, I paid for a code and everything seemed ok. When I tried to play the game a thing came up saying it crashed and then a message popped up saying The game crashed whilst initializing game     Error: java.lang.IllegalStateException: GLFW error 65542: WGL: The driver does not appear to support OpenGL. Understanding the length extension attack I have been trying to understand exactly how a length extension attack works on SHA-1. I'll detail below what I've understood so far, so that I can convey my understanding of the same and hopefully get advice on where I'm going wrong.  Lets assume that for a message $m$, a secret $s$ is appended to it and the SHA-1 hash is calculated. If $\textrm{len}(m) + \textrm{len}(s)$ is not a multiple of the block size, a certain amount of padding is added to it to make it a multiple, and the hash is generated using what is essentially $s || m || \textrm{padding}$.  Now SHA-1 internally uses 5 registers — it takes in an block, generates new register values, turns the crank, takes in another block, generates new register values, turns the crank ... and so on till the end. When all blocks are exhausted, the register values are concatenated and spit out.  Assume that an attacker knows a certain value of $m$, for which he also knows the hashed key. In such a case, he knows the state of the 5 registers when $(s || m || \textrm{padding}$ was processed. Lets also assume that the attacker knows the length of $s$, so that he can predict how much padding was added.  Here is where I get confused. From what I've read so far, the attack involves taking the known hash, adding a certain amount of padding and then the value that we want. However, isn't the padding already used up in creating the hash? Why are we using padding in our attack? Standard nomenclature for component types What prefixes should be used on reference designators for components of various types?  I think we can all agree that "R##" refers to a resistor, "C##" refers to a capacitor, and "L##" refers to an inductor.  Beyond that, it appears to be a mishmash of conventions.    I've seen both "IC" and "U" used for chips.   "Q", "T", and "M" have been used for transistors and MOSFETs.  Ordinarily, "D##" is used for diodes, but LEDs and Zeners get special treatment on some boards.    What standards are available for reference, and who endorses them?  JEDEC, ISO, IEEE, and other standardization bodies are welcome references (though I'd prefer an inexpensive standard), but I'm also curious to see what's used at various companies other than my own.    Edit:  What I'd really like to see is a list in an answer here which complies with the standard (even if it's just a quote). Tracking down where disk space has gone on Linux? I have a question that says "Show that there is a bounded sequence $x_n$ which is not convergent but has the property that $x_n - x_{n+1} \to 0$ as $n \to 0$.  What does this mean? Do I need to come up with an example or does the problem actually want me to prove such proposition?  By the way, I see that this sequence looks like Cauchy because of $x_n - x_{n+1} \to 0$ as $n \to 0$, but it is obviously not. I have a Lenovo T570 with Xubuntu 18.04 LTS. My current issue is that my cpu speed stepping is kind of going nuts and does what ever it thinks its best.  Sample: when I run my IDE and cpu load increases during build time, the governor changes automatically. I caught the moment during compiling my project with the following call:  martin@martin-ThinkPad-T570:~$ while cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor; do sleep 1; done powersave powersave performance performance   cpufreq-info tells me this:  martin@martin-ThinkPad-T570:~$ cpufreq-info  cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to cpufreq@vger.kernel.org, please. analyzing CPU 0:   driver: intel_pstate   CPUs which run at the same hardware frequency: 0   CPUs which need to have their frequency coordinated by software: 0   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.25 GHz. analyzing CPU 1:   driver: intel_pstate   CPUs which run at the same hardware frequency: 1   CPUs which need to have their frequency coordinated by software: 1   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.36 GHz. analyzing CPU 2:   driver: intel_pstate   CPUs which run at the same hardware frequency: 2   CPUs which need to have their frequency coordinated by software: 2   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.26 GHz. analyzing CPU 3:   driver: intel_pstate   CPUs which run at the same hardware frequency: 3   CPUs which need to have their frequency coordinated by software: 3   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.36 GHz.   Please take a look at     current policy: frequency should be within 3.50 GHz and 3.50 GHz.       The governor "performance" may decide which speed to use   Afterwards to go back to powersave I use my little script:  martin@martin-ThinkPad-T570:~$ cat cpu_freq_save.sh  #!/bin/bash sudo cpufreq-set -g powersave -c 0 --min 400MHz sudo cpufreq-set -g powersave -c 1 --min 400MHz sudo cpufreq-set -g powersave -c 2 --min 400MHz sudo cpufreq-set -g powersave -c 3 --min 400MHz   Which resets the min frequency and the governor but as soon as I compile again with my IDE every time the governor and the min frequency changes again.  Any idea how I can disable that automatic change?  PS: If you need more details, just tell me where to find them and I will provide them I know that an easy to handle formula for the CDF of a normal distribution is somewhat missing, due to the complicated error function in it.  However, I wonder if there is a a nice formula for $N(c_{-} \leq x &lt; c_{+}| \mu, \sigma^2)$. Or what the "state of the art" approximation for this problem might be. Disable all software installation how to prove $\mathbb Z_n$ has divisors of zero if and only if $n$ is not prime A non-zero number $a \in \mathbb Z_n$ is called a divisor of zero if there is a non-zero number $b \in \mathbb Z_n$ such that $ab\equiv 0\pmod n.$  How can I prove $\mathbb Z_n$ has divisors of zero if and only if $n$ is not prime.  I filled out the addition and multiplication tables for modulo 6 and 7 and tried to find out the relation, and it's definitely true. I know I need to prove it in both directions since it is an 'iff' question. But I still don't get it. Marketing Cloud contact builder shows 9 times more contacts How to group distinct values from a list using odata rest api Hi I have a list with two fields "Regions" &amp; "Countries" I am using a rest api to retrieve the list of just regions like so: http:mysitename/_api/web/lists/getByTitle('TaxTool')/items?$select=Region  In the results there are lots of duplicates and I was wondering how to return unique values. How do I kill entities at y=65? Potions can survive at y=65  One potion was thrown into the void, but instead of being killed, it just lingered there.  Any ideas to kill it? I can't just run /kill @e[type=!player,tag=test1]  (yes, the tag of the entity is indeed test1 ) How to fix error: The markup in the document following the root element must be well-formed I want to  GRANT SELECT     ON ALL TABLES     TO foo;   But postgres tells me I have a syntax error at "TO". It expects a GRANT like:  GRANT SELECT     ON ALL TABLES     IN SCHEMA public     TO foo;   We have a handful of tables that have been sharded such that public, shard123, and shard124 all have a table my_table, and public.my_table is the parent of both shard123.my_table and shard124.my_table. I've GRANTed SELECT to foo for public schema, but foo doesn't have permission for any of the shard schemas.  I've also done:  ALTER DEFAULT PRIVILEGES     FOR ROLE dba     GRANT SELECT     ON TABLES     TO foo;   ...which should automatically grant for any new tables and schemas made from now on.  There are 1000 &lt; n &lt; 10000 shards/schemas, so GRANTing separately for each shard/schema is impractical.  How can I GRANT to a role for all existing tables across all existing schemas (all shards)?  Or even better, can I GRANT for all schemas LIKE 'shard%'? What should I look for when buying a used bicycle? I'm moving to a city where I can ride a bicycle to the grocery store, coffee shop etc. I want to purchase a decent used bicycle. I'm leaning towards a bike that's in between a "10-speed" or road-bike and a mountain bike. What should I look for when choosing a particular bike?  I've never purchased a used bicycle. Other than classifieds (e.g., Craigslist), what types of places can I look? What other issues should I consider, such as size, visual appearance, leaking tires, etc.? How can I make sure it's not stolen? I created a view to show Users. These users can create nodes of the "Questions" content type.  The view has to render a table to show how many (the total number) Questions the user has created. Something like:  User +++ Questions created John --- 10 Ted  --- 4 Alf  --- 19 Word that means "the opposite of what you would expect" I'm looking for a word that means the opposite of what one would expect. This word might be used to express the surprise that a teenager's grandmother uses text messaging much more than he does, or that a city seems brighter at night than it does during the day.   I'm not seeking the word ironic or irony which refer to the use of something to describe its opposite experience or emotion. Should I install the play disc or not? I hear both sides of the story. "Installing both discs will improve performance" or "Playing from the disc is best".  I've come across a few threads that say to install the play disc to a USB drive. Will the Xbox 360 even read from 2 different sources at once?   Someone please clear this up for me, for all of us.  Do I Install the second "play" disc or not, and why? It's taken me almost 10 years of Linux usage to ask this question. It was all trial and error and random late-night internet surfing.  But people shouldn't need 10 years for this. If I were just starting out with Linux, I'd want to know: When to alias, when to script, and when to write a function?  Where aliases are concerned, I use aliases for very simple operations that don't take arguments.   alias houston='cd /home/username/.scripts/'   That seems obvious. But some people do this:  alias command="bash bashscriptname"   (and add it to the .bashrc file)   Is there a good reason to do that? I'm trying really hard, but I genuinely can't think of any circumstances in which I'd want to do that. So, if there is an edge case where that would make a difference, please answer below.  Because that's where I would just put something in my PATH and chmod +x it, which is another thing that came after years of Linux trial-and-error.  Which brings me to the next topic. For instance, I added a hidden folder (.scripts/) in the home directory to my PATH by just adding a line to my .bashrc (PATH=$PATH:/home/username/.scripts/), so anything executable in there automagically autocompletes.  If I needed to.  I don't really need that, though, do I? I would only use that for languages that are not the shell, like Python.  If it's the shell, I can just write a function inside the very same .bashrc:  funcname () {   somecommand -someARGS "$@" }   As I stated, I found a lot of this out through trial and error. And I only truly saw the beauty of functions when my computer died and I was forced to use the computers of the people around me when they weren't using them.   Instead of moving a whole directory of scripts from computer to computer, I ended up just replacing everyone else's .bashrc with my own, since they had never even made a single modification.  But did I miss anything?   So, what would you tell a beginning Linux user about when to alias, when to script, and when to write a function?   If it's not obvious, I'm assuming the people who answer this will make use of all three options. If you only use aliases, or only use scripts, or only use functions—or if you only use aliases and scripts or aliases and functions or scripts and functions—this question isn't really aimed at you. Favorite questions in the Android app