How can I test code with History records? I've recently developed a small visualforce component that displays any object's child's __History records.  I have to make tests with the @IsTest(SeeAllData=true) because I can't retrieve the historical records in the own test execution context (I imagine because they have not yet been inserted?).  Well, the problem I have encountered is that when deploying to a Production environment sometimes the tests don't pass because the data that my queries bring isn't consistent. But, I can't actually make them consistent because the field Field can't be used as a filter with LIKE operand and NewValue and OldValue can't be used as filters either.  Is there any way to make my tests more consistent when working with _History records?  Thanks
Is it possible to test apex that relies on field history tracking? I have some code that relies on field history tracking by querying the History for a custom object. This works fine, but it appears that the history records aren't created during the test so none of my tests will pass.
Should an image carousel on a mobile site automatically rotate? Get total amount of time between records when changed state I have a table, showing the status (healthy, broken) for each device at a given timestamp. I need to get the total amount of time of a whole breakdown.  So the data is stored like this:  device_owner   device_id    timestamp          status owner1         device_1     2001-01-01 09:00   0 owner1         device_2     2001-01-01 09:15   0 owner1         device_1     2001-01-01 09:30   1 owner1         device_2     2001-01-01 09:45   1   and so on.  The example above shows    device_1 was down from 09:00 to 09:30 (total 30 mins),   device_2 was down from 09:15 to 09:45 (total 30 mins)   What I need  Need to calculate the total amount of time for the whole breakdown for owner_1 will be 45 mins (from 09:00 to 09:45) instead of 60 mins (30 + 30).  device_owner   total_breakdown_min owner_1        45   What I've done  Currently I can define a breakdown time for each device separately (device_1 = 30mins, device_2 = 30mins). For this I transformed the table using LEAD over partition by device_owner, device_id and date part from timestamp:  device_owner  device_id     timestamp        status lead_timestamp   lead_status owner1        device_1     2001-01-01 09:00   0     2001-01-01 09:30     1 owner1        device_1     2001-01-01 09:30   1     NULL                 NULL owner1        device_2     2001-01-01 09:15   0     2001-01-01 09:45     1 owner1        device_2     2001-01-01 09:45   1     NULL                 NULL   So the datetime difference between timestamp and lead_timestamp in sum gives me the total breakdown time for a device.  ;WITH LeadStatus AS (     SELECT         D.*,         lead_status = LEAD(D.status) OVER (PARTITION BY D.device_owner, D.device_id, D.date ORDER BY D.datetime ASC),         lead_timestamp = LEAD(D.datetime) OVER (PARTITION BY D.device_owner, D.device_id, D.date ORDER BY D.datetime ASC)     FROM         #DeviceStatus AS D ) SELECT * FROM LeadStatus   It is the same device list for any owner. The data snapshot is to be taken between 2 dates (StartDate, EndDate). The records are written to a DB each n seconds and also when the device status changes. I am flying from Los Angeles to Bangalore. I have a flight option from LAX to Minneapolis and from there to Paris. I have only 45 minutes at Minneapolis before my next flight. Is this too risky a schedule? I am not an American, so I guess I would need to cross emigration too? Eigenspace of the companion matrix of a monic polynomial How do I prove that the eigenspace of an $n\times n$ companion matrix  $$ C_p=\begin{bmatrix} 0 &amp; 1 &amp; 0 &amp;\cdots &amp; 0\\ 0 &amp; 0 &amp; 1 &amp;\cdots &amp; 0 \\ \vdots&amp;\vdots &amp;\vdots&amp;\ddots&amp;\vdots\\ 0 &amp; 0 &amp; 0 &amp;\cdots &amp;1 \\ -\alpha_0 &amp;-\alpha_1 &amp;-\alpha_2 &amp;\cdots&amp;-\alpha_{n-1} \end{bmatrix} $$ equals $\operatorname{Span}\{v_{\lambda} \} $ where $v_{\lambda}$ is an eigenvector of the companion matrix w.r.t. the eigenvalue $\lambda$: $$ v_{\lambda} =  \begin{bmatrix} 1 \\ \lambda\\ \lambda^{2} \\ \vdots\\ \lambda^{n-1} \end{bmatrix}. $$ The derivation of the Hamilton-Jacobi equation using canonical transformations is typically done involving a type-2 generating function.  Is it possible to use a another type of generating function, namely type 1, 3 or 4? Forcing an 'added' alias to every command Is it possible to forcibly add a timing alias (for lack of a better way to phrase it) to every command in bash? For example, I would like to have a specific user who, whenever a command is run, it is always wrapped either with date before and after, or time. Is this possible, and, if so, how? I love R. Courant and F. John's Introduction to Calculus and Analysis because of its wide coverage, precise description and friendly written style.  Are there any classic textbooks like it on ODE/PDE?  thanks. \textcite macro produces "Author (year)" correctly but colours first paren with hyperref Warning: preg_replace(): Unknown modifier I have a website that sells music artists posters. Each artists has a page containing a small bio, and a list of posters we are selling representing the artist.  Currently our HTML looks like that  &lt;h1&gt;{Artist name}&lt;/h1&gt; bio &lt;h2&gt;Posters&lt;/h2&gt; &lt;ul&gt;   &lt;li class="poster"&gt;...&lt;/li&gt;   ... &lt;/ul&gt;   We are redesigning this page, and we have a new template that we really like. Problem is that in this new version the &lt;h2&gt;Posters&lt;/h2&gt; does not appear anywhere on the page.  As you might expect, a significant part of our traffic comes from people typing something like : "{Artist name} poster" on Google.  I fear that, by removing the word "poster" from the page, we will reduce our chances of getting these people to come to the site, since Google might down rank us.  I see several options here :   Give Google a slightly altered page that contains the H2 tags. But I think this falls into the "Black Hat SEO" category. And I don't want that. Put the heading. Hide it with CSS. Everyone wins, including accessibility tools which can determine the structure of the page using the "invisible" heading. But I do not know if this is considered a good practice. Forget about the heading, and find other ways to tell Google that we really are about posters. (via keywords, but do they really have the same "weight" as an H2?) Adapt the design to our SEO need, and find a way to put that heading nicely.   Are there webmasters out there that have been facing the same issue, how did you resolve it? Is it possible to password protect a zip file created by Windows itself (without external tools?) Why not use a WAMP stack? Show that the countable product of metric spaces is metrizable Given that $a$~$\mathcal{N}(\mu, \Sigma)$ and $\mu$~$\mathcal{N}(0, \sigma^2 I)$, Is $p(a|\Sigma, \sigma)=\int p(a|\mu, \Sigma)p(\mu|\sigma)d\mu$ again a Normal distribution? And how to estimate the mean and variance respectively? Thanks a lot! $\mathbb Z[i]/ \langle 1+2i \rangle \cong \mathbb Z_5$ In the paper "Beautiful Code Compelling Evidence", by J.R. Heard -- Code is formated in a particular way which includes margin comments. I am looking for a way to do this as I think it is a very clear way to comment comment code in a literate programming style. Prove that two distinct numbers of the form $a^{2^{n}} + 1$ and $a^{2^{m}} + 1$ are relatively prime if $a$ is even and have $\gcd=2$ if $a$ is odd.   My attempt: If $a$ is even, let $a = 2^{s}k$ for some integers $k, s$ Then, $$a^{2^{n}} + 1 = 2^{2^{n}s}\cdot k^{2^n} + 1$$ and $$a^{2^{m}}  + 1 = 2^{2^{m}s}\cdot k^{2^m} + 1$$ To prove that they're relatively prime, we need to show that their gcd = 1. And I was stuck here, how could I prove that gcd of two numbers is $1$?     A hint would be sufficient. Thanks. How to instantiate polymer component programmatically in dartlang? What prevents photons from getting mass from higher order Feynman diagrams Java Enum definition